M.L. McPherson
Last revised: Friday, August 11, 2006


What is Possible with the Marlin?

What is Possible with the Marlin?

BOLT-ACTION HISTORY

When I look at action developments that reached something of an early zenith around 1890, I see two distinct systems. First, we have the turn-bolt action design. Many hunters would argue that practically every design change in this basic system since the '98 Mauser has been a step in the wrong direction.
As manufacturers continued to look for less expensive methods of producing such rifles, particularly in the era before CNC (computer numerically controlled) manufacturing, one significant '98 design feature after another fell by the wayside, all on account of affordability – until the advent of the Savage AccuTrigger® I cannot think of one change that could unequivocally be deemed an improvement! The modern culmination of these changes is well represented by the basic Savage and Remington bolt-actions.
These receiver systems are so different from the '98 that one could argue that the only things these newer designs share with the '98 are two locking lugs and 90-degree bolt rotation! This is not quite fair as the newer designs do have an integral trigger system and a similar striker system but there, realistically, the similarities end. Every major and minor component is designed and built completely differently. A novice, when asked to compare these two receiver systems, could be forgiven for concluding that the differences far outweigh the similarities.
With CNC machining, the need for simplification, as a means of achieving affordability, chiefly through reductions in production and hand fitting time, has generally passed. The Classic Winchester Model-70 proves this point, this gun is mechanically identical to the legendary pre-64 Winchester Model-70 and therefore shares so many characteristics with the '98 that no one could fail to see that the two are very closely related in every aspect of design and function. Nevertheless, with modern facilities, the manufacturer can evidently profitably sell this rifle at a reasonably competitive price.

LEVER-ACTION HISTORY

Now, consider the classic lever-action rifle, as originally perfected, at just about the same time that Mauser was reaching a zenith with his turn-bolt designs. In that era, both Browning and Marlin incorporated vertical locking lugs into affordable designs. While generally distinct in functionality, each of these designs represents true genius. Here, let us consider the Marlin models of 1893 (hereafter the long-action) and 1894 (hereafter the short-action). These Marlin designs utilize an ingenious combination of geometric interaction with a few springs and one ratchet mechanism to connect and manipulate every working part of the receiver.
Unlike the history of the turn-bolt, manufacturers were able to maintain profitability with these complicated lever-action designs. While "modern" lever-action designs came, and went!, none of those have ever made any serious dent in the popularity or profitability of these tubular magazine designs.
Since these guns are far more intricate and use many more moving parts, compared to the '98 Mauser, one must wonder why this would be true. It would seem that the same forces that drove less expensive bolt-action designs to capture that portion of the market would have driven less expensive lever-action designs to capture this portion of the market. This just did not happen.
Consider the Model-88 Winchester. This rifle was introduced in 1955, as a replacement for the then discontinued Model-71, which was based upon the '86, one of the most intricate and therefore most expensive of Browning designs. The '88 was chambered for a round that essentially duplicated performance of the only '71 factory chambering, the 348 WCF. The '88 was far less expensive to produce and it eliminated one of the chief design weaknesses of the '71 (and all other traditional lever-action designs), the two-piece stock.
When we ignore the 17 design modifications reported to have been applied to the '88 trigger group, in a failed effort to eliminate incidental discharges, and assume that the trigger group could have been designed to work safely, we must conclude that this basic design is eminently sound. I had the pleasure of working with one of these guns chambered in 284 Winchester, about 1972. With N205 and the Sierra 160 BTSP bullet, we were able to consistently produce 5-shot, 100-yard groups that measured less than one-inch, on-centers. Our best groups measured less than 0.8-inch.
Now, while this does not sound all that impressive today, in that era, we could have won considerable cash if we had been able to find enough bolt-action riflemen willing to bet that they could shoot smaller groups with their best hunting load in their favorite factory-stock bolt-action rifle.
By the way, our pet load produced an honest 3000-fps from the 22-inch barrel and therefore belied the then popular mantra that the 284 would not perform up to velocity expectations when shooting heavier than standard bullets. I cannot know what pressure that load generated and I suspect that it was on the high side but I do know that extraction was flawless and we never lost a case to primer pocket expansion.
Then, after developing and testing our hunting loads, we carried that and my, then new, 270 Winchester, Remington 760, which produced similar accuracy, into the hunting field. Then an incident occurred that changed how I will always feel towards the Model-88.
My acquaintance and I were walking across a high mountain meadow on a clear and beautiful October day. He was in front of and to my side, perhaps ten feet away. We were walking on perfectly smooth ground. He had the '88 slung over his shoulder, so that the muzzle pointed skyward. He had a round chambered and the safety was in the "safe" position. The receiver was behind his back and nothing was touching either the sides or the bottom.
The gun fired! He froze. I froze. He slowly turned and, with his ears ringing and his face turning pale, unable to stop himself, he asked that inevitable stupid question, "Did this thing just fire?" In disbelief, we checked. Yes, the safety was fully on; yes, the chamber contained a fired case. Yes, the gun had fired itself and for no reason that anyone could possibly determine. The mechanism was perfect and it contained no grease, crud, or debris that might have resulted in this event. IT JUST FIRED!
Needless to say, considering the potential for the muzzle of that '88 to have been pointed at some portion of my anatomy, in those young and careless days, we were both dumbfounded and just a bit more than slightly concerned. Before the gun self-fired, an inadvertent sweep of the muzzle certainly would have made me nervous; after that event, it made me want to continue my hunt in a different State! Our solution was to leave the chamber empty.
Aside from that not minor problem, the '88 is a most interesting design. It incorporates an unusually rigid receiver, a decent trigger (as far as let-off goes), a front-locking action that features smooth operation and serious strength, and it has a one-piece stock that eliminates the significant problems associated with a two-piece stock. And, it has about as much appeal and nostalgia as the modern box sedan. I suspect that even if Winchester had been able to solve the trigger group problem, the '88 would have long since died.

MODERN MARLIN DEVELOPMENT

Meanwhile, in the early 70s, as the '88 was heading toward the ranks of abject gun design failures, traditional lever actions, despite significant limitations associated with the tubular magazine and the two-piece stock, never faltered. Winchester continued to produce copious quantities of the '94 and Marlin went so far as to, reluctantly, reintroduce (in response to an incessant din of requests from shooters, such as this author) their short-action 1894.
In that era, Marlin was also modifying their long-action, first to accommodate the newly developed 444 Marlin and then to handle the legendary 45-70 Government. The 444 was a modification of the basic 30-06 case and was most similar to a wildcat that had then been a popular conversion for at least a decade. The 45-70 conversion would not have been possible if the original 45-70-500 loading had not, long-since, been obsolete. The 45-70-500 is too long to work through this action and the round nose bullet would have been unsafe for use in a tubular magazine. It is quite surprising that an action designed around the 38-55 case (basis of the 30-30) could be modified to work perfectly with a case that is fully 20% larger in diameter – but, as we will see below, even the 45-70 is not the performance pinnacle for this action.
As to the reintroduced 1894, Marlin originally offered that only in 44 Magnum. I am confident that they only stood the cost of retooling for this gun because they expected that they could sell many thousands to those folks who owned and used 44 Magnum revolvers and who would, therefore, appreciate a companion carbine. Furthermore, I am convinced that the Marlin officials who made that momentous decision must have been shocked at how badly they had misjudged the marketplace.
In the subsequent thirty some years, the 1894 has been offered in a plethora of chamberings and configurations. Most recently Marlin has even offered a pistol-grip model, which belies the traditional carbine heritage but is, nonetheless, a fine gun.
Other than to suggest that continued success of these Marlin designs proves the genius of this basic system, and that the two-piece stock is still a limitation to accuracy potential (although my throughbolt conversion significantly mitigates this) I will not further dwell here with the history of these guns. What I wan to do is look at what can be done with each.

MARLIN LIMITATIONS

These Marlin rifles have what I would deem a design flaw. Perhaps surprisingly, this is not the rear-locking lug. Rather, it is the relatively small diameter of the barrel threads. When chambering modern cartridges, that work at modern pressures, having a case body diameter larger than about 0.47-inch (Mauser and 30-06 related chamberings, an interesting historical accident!) the weakest portion of these barreled-actions is the chamber, under the barrel threads.
Unfortunately, due to close proximity of the magazine port under the barrel, it is not particularly feasible to enlarge these threads. This is too bad, had John Marlin simply moved the magazine tube and loading port 0.050-inch farther below the barrel he could have enlarged the barrel threads by 0.1-inch and eliminated this weakness. The subsequent design would have worked perfectly without any other significant changes! And this does matter; early Marlins, with softer barrel steel, are prone to chamber swelling. Modern guns avoid this fate only because the steel used in the barrels has significantly increased tensile strength.
My solution to this weakness is to modify the Marlin thread, so that the thinnest portion of the chamber wall under the threads is as thick as is feasible without significantly weakening the receiver. To do this, I use a custom tool set built to my specifications by custom reamer maker Dave Manson. My friend, Ben Forkin (Forkin Custom Classics) originally persuaded Manson to make such a tool set. These tools reduce height of the unnecessarily tall square thread and true the factory cuts so that one can install a barrel with precisely fitting threads.
The improvement is significant. With a properly fitted barrel, thinnest portion of the chamber wall is about 0.035 inch thicker. This may not sound like much until one considers that, for example, in the factory 45-70 Marlin the thinnest portion of the chamber is only 0.100-inch thick! Moreover, with precise threads in the receiver, the gunsmith can fit the barrel threads so closely that the receiver can share the load. While such a design is not ideal (most manufacturers would prefer not to rely on the hoop strength of the receiver to support he chamber), it is the best that we can do with the standard Marlin.
The next weakness is the two-piece stock. With only the conventional tang bolt attachment, any such stock is prone to failure. Considering the limited amount of wood reaching forward of the tangs and the stresses associated with side loading, we are not surprised to see longitudinal cracks reaching rearward of the tangs in older, well-used guns.
The other problem with the two-piece stock is that this system makes it impossible to isolate the barreled action from the bench and associated variations in shooter hold, etc. Firing good groups with any such gun is an exercise in patience and in paying attention to details that even many serious benchrest shooters may have not even considered.
After years of serious testing, I have concluded that how the shooter holds his tongue probably matters! For sure, how solidly the shooter holds the gun and presses his cheek against the stock will significantly alter zero. In a related characteristic indicative of just how significantly these guns interact with shooter and bench, on a good day, I can call high and low hits when testing a Marlin 45-70 and I can do so without looking at the target – all I have to do is look at the chronograph! If shot velocity is slower than mean velocity the bullet will hit low; if shot velocity is faster than mean velocity, the bullet will hit high.
I mitigate these problems by installing a throughbolt that runs from near the rear of the buttstock to a hanger that I install on a replacement, hardened-steel tang bolt. With proper glass bedding, this modification allows me to significantly compress the wood of the stock along the grain (with about 1000 pounds force). Such compression monumentally reduces potential for lateral loading to result in a crack in the stock. It also allows me to bring 100% of this force to bear on the front flats of the stock, where it should be, so that buttstock and receiver are bonded in both the vertical and the lateral plane, to the extent possible. Finally, because the tightened throughbolt bends and stretches the tang bolt it automatically clamps the rear of the tangs onto the corresponding flats in the stock, which further improves vertical rigidity.
I owe this idea to my friend Steve Meacham, who uses a more elegant version in his excellent reproduction 1885 Winchester rifles. In those rifles, with the right chambering and best loads, I have proven consistent varminting accuracy with the 225 Winchester consistently producing groups in the 2s. This would simply not be possible if buttstock and receiver were not so well bonded.
Another problem with any such rifle is the tubular magazine and foreend that must necessarily hang from the barrel in some manner. On two-piece stocked guns without a tubular magazine, it is feasible to hang the foreend independently, using a separate receiver protrusion. In an effort to improve accuracy, practically every manufacturer who has ever made such a gun has tried this approach. Almost invariably, such a design proves to be less accurate! The reason for this is the tuning fork effect. With such a design, inevitably, barrel and foreend will vibrate independently. These vibrations will just as inevitably reinforce each other.
The best solution I have found came to me from custom riflesmith Keith DeHart. It is high tech and involves one of those situations where we can say, if Browning had had it, he would have used it! This solution is to simply ensure that foreend and magazine tube do not touch the barrel anywhere other than where this is necessary and to then create a bed of RTV silicone between these pieces.
What the silicone does is to effectively kill vibrations while helping to isolate the barrel from variations in shooter hold and bag placement. Along with proper buttstock bedding and the throughbolt, the accuracy improvement for bench shooting is impressive. This difference is not so much a matter of what the gun may occasionally do, but what it will repeatedly do. For example, I expect a modified Marlin to shoot three-shot groups under one-inch using any decent modern ammunition. With several rifles, I have seen five-shot groups approaching the one-half MOA benchmark, which is rather impressive, considering the accuracy limitations of the hunting bullets involved in these tests.
An obvious limitation to each Marlin design (long and short action alike) is maximum potential cartridge length and maximum potential cartridge diameter.

IMPROVED CHAMBERINGS

Now, to the heart of the matter, just exactly what is the limit for cartridge diameter and length in each of these basic Marlin designs? The short answer is provided in the following table.

Cartridge lengths indicated require significant albeit feasible action modifications. These alterations do not in any meaningful way weaken or compromise functionality of these actions. Furthermore, action manipulation force and finger lever travel are identical to stock Marlin rifles (assuming the same level of action smoothing).
Case designs suggested in the table just happen to represent all that is feasible to accomplish and, by quirk of fate, basic cases useful for each are now readily available from Starline (50 AE and 50/110 WCF). Maximum performance with each will occur when firing bullets of 0.510-inch diameter. However, in the short-action gun, reliability and smoothness of action manipulation will likely be compromised if we try to go to that bullet diameter, which will require a cylindrical case, rather than the slightly tapered case used with the 50 AE and 0.500-inch bullets.
A similar situation exists with the basic 50/110 case (which is slightly shortened and given a slight bottleneck for use in the Marlin as the 510 Kodiak Express); we could expand this case to cylindrical and thereby use bullets of about 0.525-inch diameter. However, even if such bullets were readily available, it would be difficult to achieve smooth action functioning. Hence, we are realistically limited to bullets of 0.510-inch diameter, which is convenient since such bullets are readily available.
Of course, chamberings based upon necked-down versions of each of these cases are feasible. In the short-action gun, we can envision potentially useful conversions with bullet diameters as small as 30-caliber. Bullets designed for the 30-30 will be useful in such a case and, by quirk of fate, cannelure placement and case length are perfect! For this reason alone I have just decided that my next Conversion Marlin will be a 30-caliber on the short action.
In the long-action gun, realistic bullet design limitations and the modest potential BCs that are available with any flat point bullet (as required for safe use in a tubular magazine) would argue against any chambering smaller than 35-caliber. Here, bullets designed for the 356 Winchester would be marginally useful – the caveat is a result of the potential velocity that this relatively large case could generate; very likely, existing bullets will not hold together on close-range impacts if launched with full-pressure loads from this chambering.
In the table below, we will assume that ideal jacketed or cast bullets, as applicable, could be obtained for each of these hypothetical chamberings. In some instances, this is a reasonable assumption; in others, it would require new bullets. In either case, the following table suggests limits of performance potential with the modern short- and long-action Marlin.

Notes: all loads in this table assume the existence of an ideal propellant and that loads are at or near the 50,000 psi pressure limit that will assure smooth extraction and safe use. Realistically, generally, actual performance of best loads should come reasonably close to these predictions. Lengths for some of the hypothetical cast bullets would vary, depending upon actual design and alloy and, therefore, potential velocity could vary by about +/- 50 fps for such loads. Performance comments for jacketed bullets are based upon intended design velocity and may or may not reflect reality (history has demonstrated that just because the bullet was supposedly designed for a given muzzle velocity does not mean that it will perform properly when launched at that velocity!).

CONCLUSIONS

As I have safe loads that generate 4000 foot pounds of muzzle energy in my modified 45-70 Marlin, the predictions for the long-action gun do not surprise me. Similarly, as we have already built short-action guns in 475 Linebaugh and 50 AE, we know that performance potential is significant – for example, in the original 16-inch barreled conversion 475, factory loads launch the 420-grain cast bullet at about 1650 fps and thereby generate 2540 foot pounds of muzzle energy, so it is not hard to imagine that the longer load in the larger bottlenecked 50 AE case would reach the performance levels indicated. What surprised me was the discovery that loads in properly necked down 50 AE cases will significantly surpass factory 30-30 and 35 Remington ballistics, respectively.
So, what is possible with the modern Marlin rifle? Certainly far more than Mr. Marlin could have dreamed. As to accuracy and dependability, likely far more than most shooters would ever expect. As to performance potential, with the right loads in the right factory and wildcat chamberings, these guns are suitable for practically any application, worldwide.
Note, in the above text and in the picture captions, I have used monikers that may require a bit of explaining. First is the KE abbreviation, this stands for Kodiak Express but it is reminiscent of Kinetic Energy, which is no accident. Basically, I have chosen to dub any necked-down version of the 510 KE with a name reflecting bullet diameter (in thousandths of an inch) followed by the KE moniker.
Second, is M³ (pronounced M-cubed), this stands for McPherson Marlin Maximum. I probably would never have thought of this and probably would not have used it if I had thought of it. However, Dave Manson suggested it and, upon reflection, if it is good enough for him, it is good enough for me. It certainly captures the essence of the matter, for each given bore size, these designs produce all the performance possible in the short-action Marlin.
Names applied in the picture caption generally reflect caliber followed by M-cubed but exceptions exist. The 44 is actually a 42- or 43-caliber gun – depending upon how one defines caliber – but can you imagine a 43 Magnum! Or a 43 anything for that matter, just does not roll off the tongue; I used 475 for the same – how does it sound – reason; since 45 would lead to confusion over correct bullet diameter, I used 458 for the 45-caliber version).
I do occasionally do a bit of gunsmithing on Marlin rifles. Those interested are hereby invited to visit my web site: levergun.com.

A note on the photographs: Other than the 44 M³, which uses the standard 440 Cor-Bon case, the bottlenecked designs depicted in the following pictures are mock-ups made with tools at hand. In some, shoulder angle matches what I would probably use in the actual design (30-degrees); in others, it does not. Neck lengths are approximately correct – all such designs are intended to have a case neck with an outside length that is about two-thirds of groove diameter.
Body taper on all mocked-up cases is exaggerated. On M³ examples, I would eliminate the modest taper from the 50 AE case. Similarly, in the KE designs, I would use the same taper as the 510 KE, which is about one-half that of the 50/110 WCF case (used to make these mock-ups) – the tiny bottleneck on the 510 KE is included to prevent chambering in a 50/110 chambered gun.
 

1) 1894 Conversion 50 M³ in port bottom view
This view shows a 50 M³ cartridge partially inserted into loading port. This port was one of the few things on the receiver not requiring modification for this conversion. This case just barely enters, if case diameter were any larger this conversion would not be feasible because case would not eject from receiver -- case diameter would exceed bolt-opening height! Cartridge overall length for the various M³ wildcat conversions is set near 1.83-inch, which takes advantage of maximum feasible cartridge handling length of this receiver (requires significant modifications to many parts but does not alter finger-lever travel or increase action manipulation force!).

2) Selected 1894 Conversions
Left to right: 50 AE (a simpler but significantly less powerful 1894 conversion), 50 M³, 475 M³, 44 M³, 30 M³, 44 Remington Magnum (for comparison). Consider that the 50 M³ easily generates twice the muzzle energy of factory 44 Magnum loads. With performance significantly surpassing even top-end 30-30 handloads, the 30 M³ changes the character of the Marlin carbine; loaded with the unusually efficient Speer FN bullets; this is a genuine 300-yard deer chambering.

3) Deceiving comparison 30 M³, versus 30 WCF
Case diameter matters; so does permissible chamber pressure. While factory 30-30 loads generally produce only about 2250 fps with 150-grain bullets, maximum handloads that reliably extract freely may reach 2500 fps (safe in some strong, modern guns); conversely, the 30 M³ (right) easily reaches 2550 with the 150-grain Speer FN. The excellent Speer 130-grain FN reaches 2750 fps and is an outstanding option for all lighter deer species.

4) Loading 50 M³ into 1894 chamber
This is the proverbial “fit” – no extra room, either in length or diameter. If case were any larger in diameter it would not eject.

5) Ejecting 50 M³ from 1894
This view demonstrates degree of fit between this cartridge and this receiver. Without building a new (taller) bolt and widening receiver opening, to accommodate that (which is not feasible), a larger diameter case could not be used in the 1894 Marlin. Since the 50 AE case is only about 0.020 inch smaller than maximum feasible case diameter (without running into pressure limitations, to prevent overstressing the chamber), this is not a significant restriction.

6) Ejecting 30 M³ from 1894
This looks rather odd but it is difficult to argue with performance. Loaded with the unusually efficient 130-grain Speer FN, at 2750-fps muzzle velocity, this is a serious 300-yard chambering. Terminal performance testing of all available 30-caliber tubular-magazine bullets suggests that this bullet, despite the unusually low mass, against smaller species, this is among the most effective of all bullets designed for the 30-30.

7) Selected 1895 Conversions
Left to right: Starline 50-110 WCF case (Buffalo Arms offers redrawn 348 WCF cases trimmed to correct 50 Kodiak Express length; these are fully 25 grains lighter than Starline 50/110 cases); 510 KE, 458 KE, 358 KE, 45-70 Government (for comparison). As an example of potential performance in the converted 1895 Marlin, with these and similar cartridges in calibers from about 35 to 50, the 458 KE easily duplicates standard 458 Winchester Magnum loads. If we could get properly constructed bullets, the 35 KE would certainly be a serious 300-yard elk chambering. However, no such bullet now exists, the 35-caliber Speer FN bullets are too long (proper crimping would require a shorter case neck, which is certainly feasible) but I must note a concern about using any bullet with such a small meplat in a tubular magazine gun generating this level of recoil.

8) 1894 Conversion Cartridges as of March 05
Left to right: 475 Linebaugh, 44 M³ (McPherson Marlin Maximum), and 50 Action Express. These chamberings function perfectly in rifles we have already built.

9) 1894 Conversion Cartridges
Left to right: 44 Magnum and 454 Casull (for comparison); 41 M³ (McPherson Marlin Maximum), 44 M³, 458 M³, 480 Ruger (fires in 475 Linebaugh conversion rifle), 475 Linebaugh, 475 M³, 50 AE, and 50 M³. From left to right, these represent a few of the feasible conversion chamberings for the 1894 Marlin. (Note that bullets used in some of these mocked up prototypes are wholly inappropriate, longer cast bullets would be superior choices for some.)