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I got to wondering recently. Typically, if that goes on long enough, the ol’ measuring stick comes out, then unusual credit card charges begin to appear, and before you know it, there’s a fresh pile of chips on the mill table. Sometimes a small pile of discarded parts sacrifice themselves to the cause of science. Tragic, yes, but necessary, and not without ceremony, which mostly involves uttered incantations that would prevent the offending part from having a place in heaven. But let me assure you, dear reader, that no parts were harmed in this recent experiment.

The thing I got to wondering about was this: I was looking online at the .308 Marlin Express FTX bullet—you know, the one with that tantalizingly slender ogive, and the way it wears that cannelure…well, let’s just say it doesn’t leave much to the imagination. And that ballistic coefficient! Are you kidding? Fast and easy, just the way I like them. Kind of makes Hornady’s companion bullet, the .30-30 FTX, look a little stodgy.

So I got to wondering, what if we could stuff that 308 Marlin Express FTX bullet into the .30-30 case, leaving more room for powder, and picking up higher velocity and BC in return? Stop me if you’ve heard this one before.


Some off-the-cuff calculations indicated that the cartridge overall length (COAL) would be at least 2.68”, which is a fair step up from the 2.55” to which the factory Marlin 336 action is limited. I also guestimated that I would have room for an extra 3 grains of powder in the case.

Oh ho! I knew that I could stretch the action capacity of the 336 to accommodate such a cartridge, so all I had to do was hustle two blocks over to 10-Ring, our local purveyor of fine reloading supplies. Faster than I could say, “Marlin Express,” I had a box of the sleek .308ME bullets in hand, and the project was off and running.

If any of you have read my previous articles, you know that a short time back we reamed a Marlin 336 .30-30 to Ackley Improved (AI), and saw some major improvements, both in performance and accuracy. Since that rifle already had increased case capacity, I thought it would make the ideal subject, which, I reckoned, might end up rubbing elbows with the elegant 308ME itself. Or if not rubbing elbows, at least be admitted to the party.

The RPP 30-.30 AX
I decided to call this stretch limo the .30-30 AX, as in Ackley eXpress, or eXtra, or eXtreme—whatever. You get the idea. It’s not a new cartridge—the rifle undergoes more changes than the case—but there needs to be some way of referring to it, so there you are.
Marlin 30.30 Cartridges.jpg
With the AX-conversion to a rifle, the idea was to duplicate the ballistics of the .308ME cartridge with the more common .30-30. As it turned out, the 308ME bullet, seated to the cannelure, brought the new COAL to 2.71”, a stretch limo indeed, but certainly within the structural limitations of the 336 action. Furthermore, I found that the slender ogive of the new bullet did not necessitate cutting a longer leade in the chamber—in fact it would have a slightly longer jump to the lands than a factory loaded bullet! This meant that factory Marlin .30-30 cartridges could still be fired in the chamber with no loss in accuracy potential, a fact which pleased me, as it further broadened the potential of the modified rifle. This new .30-30 AX cartridge looked a lot less like an old Saturn rocket, and a lot more like, well, an entirely more modern boondoggle capable of launching sleeker projectiles into space.

Quite piqued now, I handed my test rifle over to the shop elves, who probably consulted with Gandalf or some such, worked their wizardry, and brought the gun back to me looking much the same, but with a new digestive tract capable of swallowing (and spitting out) .30-30 AXes by the handful. Sweet. You may find this hard to swallow, but believe me, there must be elves in the machine shop. The only other explanation is that my partner and I have found a way to actually be in two places at once. And if Occam’s razor means anything, that’s just silly talk.

Hand loads and load testing
Meanwhile, I’d been at the reloading bench, filling fire-formed .30-30 AI cases with dangerously heavy charges of LEVERevolution® powder. It worked out that a charge of roughly 41gr of LVR powder would max out the capacity of the case, with the bullet resting on powder, cannelure at the case mouth. For comparison sake only, a factory Marlin .30-3.0 case, or a .30-30 AI case, when paired with the Hornady .30-30 FTX® bullet, will fit about 35 and 38gr respectively. For the substantially fatter 308 ME-FTX cartridge, Hornady lists a maximum charge of 42.6gr. with the 160gr FTX bullet. I’m no fool. I did not start my new loads at 41gr, nor did they end there.

But I did get into the high 30s on my first run to the range. On a 95 degree Texas afternoon, I ran test loads up to 40 grains before encountering a sticky lever and unusual shot dispersion. The previous 39.5gr charge had given me a 5/8” group at 100yds. But I’d found the outer limit, and reversed course immediately.

Having proofed the concept with promising powder charge weights and accuracy results, the next step was to get out to our private range, where we could set up a chronograph to get some useful data, and then crack a couple of brews and discuss the results. This my partner and I did a couple of weeks later. And the results were worth discussing.

First, I should point out that our load testing has been far from exhaustive, and that any hand-loader should approach recommended maximums with caution. We loaded in Hornady cases, which are some of the heavier ones available, and did our shooting on a very hot day, so the loads mentioned should be safe, but individual discretion is a must in this sport.

In a nutshell, we stopped testing the 160gr (ME-FTX) load with 38.5gr of LVR powder (after backing away from a high of 40gr.) This load yielded an average muzzle velocity of 2530fps out of our 20” factory test barrel, a speed within 100fps of the 308ME out of a 22” test barrel, according to Hornady’s handbook. If one subtracts the usual 50fps per inch of barrel, then the two are practically identical. Another .5gr of powder might be perfectly safe, but I feel that 38.5 is a safe place to stop, and gives all that should be expected of the .30-30 AI case.

Given the potential flexibility of this improved platform, I wanted to experiment with at least one other bullet. I chose Speer’s 130gr Varmint HP, thinking that it would be outstanding on predators at longer ranges. I was not disappointed with its performance. Accuracy was spectacular, with the first 3 shot group clovering tightly at 100yds, pushed by 39.6gr of LVR. Velocities averaged about 2675. Later, running out of time and prepped cases, I grabbed a few of random weight, and fired a five shot group of the same powder charge at 200yds. The rounds printed in a perfect vertical string of 2.5”, which wouldn’t be worth mentioning, except that the impact point of each round correlated precisely with its clocked muzzle velocity. This leads me to suspect that weight sorted and carefully prepped cases would print easy sub-MOA groups at 200yds and beyond. A better barrel than the one on our test rifle might halve that.

NOTE: the 130gr has special needs in a tubular magazine. While its gaping hollow point poses no danger of igniting primers, the crisp edges of the meplat tend to cause feed jams because the bullet noses don’t like to lift out of the slightly recessed primer pocket of the succeeding cartridge. I found that imparting a shallow chamfer at the primer pocket rims alleviated jamming. An extra step in case prep, but worth it for the bullet’s performance. Otherwise, feeding and ejection were flawless in our test rifle.

At this point, our testing has been limited to just a couple of bullet and powder combinations. But some useful and interesting data has been collected on the way. We know that the .30-30 AX loads are capable of fine accuracy without modifying the chamber or leade in a manner that precludes accurate shooting with factory .30-30 loads as well. We also know that maximum charge weights of LVR powder do not fill the case entirely, so there is room in there to play with potentially more temperature stable extruded powders, like Hodgdon Varget and the like. And finally, we know that the AX loads are, for all intents and purposes, a ballistic copy of the 308 Marlin Express.

Why not just buy a new 308 Marlin Express Rifle?
The answer is there are no compelling reasons not to. If you have the spare cash for another rifle, and don’t mind getting into another caliber, the MX is a fine platform, with a well sorted cartridge. But, while it may have been well received, only time will tell if the combination has any longevity in the marketplace. The .30-30 on the other hand, has been around the block a few times, and despite a steady onslaught of newer, better, faster hunting cartridges, the popularity of the original shows no sign of abating. You probably have at least one in your safe right now.

And therein lays the advantage of the .30-30 AX improvement. If you reload, then these straightforward modifications may be the most economical (and satisfying) way to bring more power and range to your lever gun hunting grounds. Keep the rifle you have, and expand its flexibility. Whether you want to drill coyotes and varmints across a field, take deer at distance, or bust boars close up, your old friend will have fresh, virile blood in its veins. You may see a different rifle breathing with a deep, steady confidence under that care worn varnish. And you will have a recipe book full of options (not to mention heat-and-serve dinners) when feeding time comes around.

Marlin 336 rifle modifications for .30-30 AX
So now, to nuts and bolts. The required modifications to various parts, including the receiver itself, are irreversible. However, as previously mentioned, they are completely backwards compatible, and not especially evident to the casual observer. Our AX-converted rifle will feed, fire, and/or eject all factory .30-30 cartridges, as well as cartridges fire formed and handloaded in .30-30 Ackley improved brass. Reloads may use any .30-30 bullet in addition to bullets with longer ogives/seated lengths, like the one Hornady sells for use in the 308 Marlin Express cartridge, as well as a number of others, as long as they have tips that are safe for use in tubular magazines.You may not fire factory 308 Marlin Express cartridges in the AX-improved rifle.

Think about that. Look at the options. Look at the ballistic coefficients. If you find them too tantalizing to resist (as I did), then call us. We charge $300 for the conversion. Otherwise, carry on.

May the sun be at your back, and the breeze upon your face. Happy hunting.

Best,
Adam Devine


 

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Discussion Starter #4
Nice writeup!

But no pics of the rifle? or targets? Haha...
Good point! Will have to get those taken and added!


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Marlin 336 rifle modifications for .30-30 AX
So now, to nuts and bolts. The required modifications to various parts, including the receiver itself, are irreversible. However, as previously mentioned, they are completely backwards compatible, and not especially evident to the casual observer. Run a factory .30-30 cartridge through, and you won’t notice any difference until the spent case emerges in a different shape (like any AI chamber, there will be a modest loss in velocity with factory loads). But you will have a rifle capable of reliably digesting virtually any .308 cal bullet that can safely be used in a tubular magazine.
Interesting so if I couldn't reload this shell myself, I could fire a .308 Hornady with the red flex tip in my .30-.30 if it was converted to a .30-.30AX? I must be missing something.
 
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Interesting so if I couldn't reload this shell myself, I could fire a .308 Hornady with the red flex tip in my .30-.30 if it was converted to a .30-.30AX? I must be missing something.
Our AX-converted rifle will feed, fire, and/or eject all factory .30-30 cartridges, as well as cartridges fire formed and handloaded in .30-30 Ackley improved brass. Reloads may use any .30-30 bullet in addition to bullets with longer ogives/seated lengths, like the one Hornady sells for use in the 308 Marlin Express cartridge, as well as a number of others, as long as they have tips that are safe for use in tubular magazines. You may not fire factory 308 Marlin Express cartridges in the AX improved rifle. The idea was to duplicate the ballistics of that cartridge with the more common .30-30. Sorry if I didn't make that perfectly clear in the article.

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Discussion Starter #7
Nice writeup!

But no pics of the rifle? or targets? Haha...
By the end of that hot day of shooting (rough work!) cold beer sounded much more appealing than hiking and photography:beerglass:
 
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Adam, I read the article with several extended interruptions, so my digestion was compromised. If these points were covered please forgive my redundancy.

The AX is simply a 30-30 AI case fueled with LVR powder, right? Have you completed testing with other projectiles in addition to the two mentioned?
Did you modify the rifle (trigger, bands, springs, screws) in order to enhance accuracy?
Very interesting read, written with flair and panache.
Ss
 
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Adam, I read the article with several extended interruptions, so my digestion was compromised. If these points were covered please forgive my redundancy.

The AX is simply a 30-30 AI case fueled with LVR powder, right? Have you completed testing with other projectiles in addition to the two mentioned?
Did you modify the rifle (trigger, bands, springs, screws) in order to enhance accuracy?
Very interesting read, written with flair and panache.
Ss
Hi Sidespin,
Thanks for tuning in. Glad you enjoyed the article. You are essentially correct about the AX being an AI case fueled with LVR powder. We did not modify the case in any other way. It was our mods to the rifle platform that allowed us to seat longer, sleeker bullets and gain more powder capacity in the case. The AX loads pick up about 100fps over an AI running Hornady .30-30 FTX bullets. With the higher BC 308ME projectiles, however, the AX will carry more than 1000ft/lbs of energy to 400yds, as opposed to 300yd for the standard AI, with several inches less drop at that distance. At 500yds the AX is still pushing nearly 900ft/lbs of energy--more than enough to drop a deer, assuming you wanted to take such a shot.

I haven't had the chance to test any more projectiles since writing the article, but Speer's Grand Slam line is intriguing. Cannelure's in the right places, and pretty good BCs. Of interest is the fact that the Speer 130 HPs we tested can be seated right up to the lands (I moved them back .020") which may be partially responsible for their superior accuracy. I would also like to find a suitable powder that will give near optimal velocity while filling the case densely and reducing the need for a cannelure. That would introduce more suitable candidates, like Sierra's 165 Game King HP. And call me crazy, but I'm tempted to do some controlled testing to see if typical polymer ballistic tips are even capable of popping primers. If not, things could get even more interesting.

Our test rifle has had some accurizing work. As noted in my previous article on AI chamber reaming, this rifle started out a horrible (2.5"+) shooter and now regularly shoots close to MOA with most loads, sometimes well better. Still not the best shooter we've built, but considering where it started, we're happy enough. Given what I've seen with this experiment, it's only a matter of time before I make these mods to one of my personal rifles.

Best,
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I did some testing in a 336 rechamber to 307 with Nosler 150 grain ballistic tips. No primer went off. In all honesty I think you would be just fine.
 
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I did some testing in a 336 rechamber to 307 with Nosler 150 grain ballistic tips. No primer went off. In all honesty I think you would be just fine.
Thanks Bryan,

I probably still will do some rigorous testing of my own (and publish methods) before I recommend it to anyone. I suspect, however, that you're right. In my experience it doesn't take much trauma to shove those polymer tips down into the nose cavity. Deformation of the bullet tip seems more likely than primer detonation.

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I was doing heavy loads as well. The cases in the tube were loaded with primers and bullets with no powder inside. Was using winchester large rifle primers. Don't know if I would try the softer federal or not but they would probably be fine as well.
 

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I think I'm going to lengthen the action on my 307 and use the 308 me ftx bullets. Works out to be exactly 2.68"
 

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seems like the primary weak link is the comment about shooting 30-30 ammo
in the modified chamber. Though I would never do it, and it might work ok in a real pinch, but the the excessive working of the brass would severely limit the long term usefulness. I doubt the brass would last through many firings.
With a normal 30-30 load, brass lasts quite a long time, though I wouldn't say indefinitely.
Given the other extra effort, I'll take the old 30-30 as is.
It remains quite good enough without all the hassle.
However, your original post and discussion was very good.
 

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Good information Bryan.

Adam, I hope I am not asking too much to request specifics regarding the accurizing you performed... Can you give some detail as to what you replaced, adjusted or eliminated?

I have a 70s Texan I'd love AI. I've been holding off till I retire and actually have time to do something besides work.
What other smithing do you do?
Thanks for the information.
 
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I was doing heavy loads as well. The cases in the tube were loaded with primers and bullets with no powder inside. Was using winchester large rifle primers. Don't know if I would try the softer federal or not but they would probably be fine as well.
Thanks again Bryan, for the helpful info.
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Good information Bryan.

Adam, I hope I am not asking too much to request specifics regarding the accurizing you performed... Can you give some detail as to what you replaced, adjusted or eliminated?

I have a 70s Texan I'd love AI. I've been holding off till I retire and actually have time to do something besides work.
What other smithing do you do?
Thanks for the information.
No trouble, Sidespin. Before I write a length reply though, check out the article on our website blog section on accurizing the 336. It may not provide all the detail you want, but it should give you a pretty good idea. If you still have questions after reading that post, I'm happy to answer, where my lawyer will permit me:shot:

While we do specialize in Marlin lever actions, a lot of our walk in work runs the gamut, and we have the experience and equipment to fix or modify just about anything. That said, we have our preferences, and a few types we'd just as soon pass on. For example, we think the Springfield XD and XDm pistols are outstanding, and we do some of the best trigger work available on any striker fired handgun on those. We're also big fans of Savage bolt actions. And CZ pistols and rifles. ARs, we can build in our sleep. But then, plenty of people (non gunsmiths included) think they can. While we won't turn away someone who wants 1911 work, we don't go out of our way to attract that business. Everyone and their brother "specializes" in 1911 work nowadays. Same with Remington bolt actions. But the only thing we turn away is cheap junk. Invariably, cheap guns cost more to fix than they're worth. It's a no win situation.

The longer I stay in the business of building custom Marlins, the more I realize that few gunsmiths have in depth knowledge of these rifles. They are a study in elegant simplicity, and yet each part has more than one critical role. It does require some study to understand the synchronized dance happening inside that receiver. Shooting sports today are dominated by "tactical" bolt actions, semi-auto pistols, and MSRs, all of which I understand and appreciate. It's hard to fault any gunsmith for making a living working in those three categories. Unfortunately, I have on more than one occasion spoken to a "master gunsmith" (a self proclaimed honorific I would not comfortably wear) who does not have much more than a passing familiarity with Marlins. And then sometimes I'll talk to an ol' cowboy action guy who sounds like he invented them. I love this business.

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Adam,

Did you say anywhere which model you used for this adventure?

I just bought a Texan in June, old and worn on the outside but solid with crisp rifling on the inside... I would consider such a conversion. However, I need to know if accurizing would "take", thus my question. I want accuracy to be a part of the equation or the dollars spent on the conversion are of little benefit.

Again, thanks for the information and guidance.

Ss
 
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seems like the primary weak link is the comment about shooting 30-30 ammo
in the modified chamber. Though I would never do it, and it might work ok in a real pinch, but the the excessive working of the brass would severely limit the long term usefulness. I doubt the brass would last through many firings.
With a normal 30-30 load, brass lasts quite a long time, though I wouldn't say indefinitely.
Given the other extra effort, I'll take the old 30-30 as is.
It remains quite good enough without all the hassle.
However, your original post and discussion was very good.
1911,

Thanks for reading. I can completely understand if you don't see the added value in such a conversion, though I believe the 30-30AI brass would last nearly as long as any other factory brass, provided it was resized only to AI specs and loads were kept modest in pressure. The beauty of reloading is that we have so much control over those factors. Like you though, I will always have at least one good ol' .30-30 kicking around. Might not scream, but it gets the job done.

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Adam,

Did you say anywhere which model you used for this adventure?

I just bought a Texan in June, old and worn on the outside but solid with crisp rifling on the inside... I would consider such a conversion. However, I need to know if accurizing would "take", thus my question. I want accuracy to be a part of the equation or the dollars spent on the conversion are of little benefit.

Again, thanks for the information and guidance.

Ss
Understood and agreed. Extra range isn't worth much without accuracy. If your Texan's bore looks good, and the rifle shoots fairly well, there's no reason it shouldn't be a good candidate for accurizing work. There is nothing in the design that precludes it. The test rifle we used for this adventure was a plain old pre-safety 336. Whether we're dealing with barrel bands or caps and tenons, great results can be had.

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