'06 Marlin 94 25/20 keyholes, leading

[Boolseye]

166136166134Hi folks – I am smithing a 1906 model 94 marlin 25/20 for my dad. The gun is shooting keyholes with 258 sized GCed bullets – I will slug the barrel, but the bore has pretty faint rifling. There is some pitting, but not too bad. I believe I scrubbed out all the lead, and I'm throwing it out to the experts for suggestions. Fire lapping? slug it and just shoot it? Thanks in advance. The goal is 4" groups at 50 yards, nothing special. Here's a couple pics of the old girl. Note the three notches on the underside behind the action.
– JP

[clum553946]

What weight bullets?

[square butte]

I would shoot the largest diameter you can chamber. My guess is that .260 will work much better for you. Other advise is to go to the Marlin Owners website and find the forum on 25-20 reloading. There are over 125 pages of pure gold for anyone who shoots 25-20. You will find the answers to your questions there - and then some. Be prepared to take some time reading. 25-20 can be finicky

[Ballistics in Scotland]

Try slugging the bore to different points in its length. If a bullet pushed three or four inches in is just a trace larger in diameter than one expelled at the muzzle, that is fine. But if there is much of a difference, it can allow bullet tipping and/or gas leakage that with erosion of the lead will never stop. Look also for wear at the muzzle (one-sided wear is the worst) by unwise use of a cleaning rod.

If it is just a case of faint rifling though, jacketed bullets might work better.

Other than the problem described, it is a very nice rifle, which I like better than the recent ones, even before the crossbolt safety. It is also a genuine LL Heburn square-bolt centrefire. But it isn't such a pristine collector's item that you need be afraid to dent its originality in any way. If easier methods fail, it could be a good candidate for reboring or lining. You won't get back on its cash value, either kind of expenditure, but it could be a rifle that would make your dad very happy.

[Boolseye]

Thanks folks. I will post results after I do some research and work.
-BE

[northmn]

If you are getting leading and tumbling the bore is likely over size as leading can be related to undersized bullets. I suspect that appropriate molds are difficult and expensive to find in the 25 caliber. Also sometimes one runs into the issue of the appropriate bullet not chambering. Seen that in the 38-55 where many use the Starline brass to be able to chamber the bullets needed for the bore. Others have had the throat reamed. Black powder can slug bullets to the bore with lead tin alloys. I don't know about the subs like 777 but it would be nice if they did. I would try 3f or equivalent first. Also need special lube like SPG.

DEP

[square butte]

NOE has several good molds in their catalog that cast at .260

[Ballistics in Scotland]

Black powder can slug bullets to the bore with lead tin alloys.

This is a good point. A lot of people think that very hard bullets, if that is what you are using, will resist leading better. So they might, other things being equal. But if they start undersize, they are likely to stay undersize, and permit byblow of gases when a softer bullet would expand to seal the bore.

[pietro]

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I wouldn't rule out an issue with the muzzle crown, and/or worn rifling there, usually caused by years of cleaning from the muzzle.



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[1Hawkeye]

Ditto on checking the crown. 25-20's can be as finicky as a 22 hornet to load for what powder are you using? And is the rifleing just shallow or is it washed out?

[35remington]

I have bullets up to .260-.262." You might want to try something similar in oversize, assuming it chambers freely. Bad rifling and undersized bullets both cause keyholing.....you may have both.

[Boolseye]

The rifling is quite washed out, very faint. The muzzle seems OK, beveled a little uniformly.
I beagled my mold and got the boolits up over .260. I was thinking maybe try 3-4 grains of trail boss, unsized, no gas check. Would need another sizer to apply the GC and keep them big. Think I should pick up a NOE expander plug so as to open up the neck a little more?

Edit: slugged the bore. Gun is basically smooth bore, barely detectable rifling on the slug, and tight, .253" at the widest. Hmmm...hopeless?

[Ballistics in Scotland]

That does sound like the problem is the rifling. It takes a tremendous amount of shooting to wear out a conventionally loaded .25-20, but it can be done. While an uneven crown can cause bullet wobble and inaccuracy, I believe it would usually be visually detectable if it produces actual keyholing.

If you do suspect the crown, you could file the muzzle totally flat, with 90 degree edges all around the bore. The only purpose for a muzzle crown is to prevent one-sided denting of the muzzle by accidental knocks. So you could eliminate this cause of inaccuracy before you get any accidental knocks, and worry about proper crowning afterwards.

But it is difficult to detect localized disappearance of the rifling in the last inch or two at the muzzle, as bad cleaning or frequent scrubbing out of atmospheric rusting might produce. It is worth driving bullet into the muzzle to test for this.

Beagling the mould, while a useful and ingenious process, isn't a totally certain prevention for leading. It widens the bullet in only one direction, and if the bullet was undersized, the gases can erode it slightly figure-of-eight shape, still depositing some atomized lead on the bore ahead of it. I don't think, though, that leading, unless extreme, would produce keyholing. You would probably be able to see lead on a new phosphor bronze bore brush after vigorous use.

I don't know what bullet weight you are using, but a .25-20 would very likely have about a 14in. rifling twist, which ought to stabilize a little over the common 86gr. I still think jacketed bullets are worth trying. If you have a friend who uses them, and it would let you out of buying a full box, pointed bullets can be tried as long as you don't load them from the magazine, and heavier ones filed flat should be good enough to find out if they eliminate the keyholing.

[Boolseye]

many thanks, BIS, for your thorough and informed commentary.

[northmn]

One very good alternative whcih you likely would not like is to send it into the JES and get it rebored to 32-20. Lots of rebores were done in the old days to handle issue like you have. Check the Marlin site for his contact. Kind of like the 35-30 that was developed to rebore shot out 30-30's and 32 Specials. There is a gunsmith on this site that does lining which is another possibility. Otherwise you are kind of dealing with a wildcat. Faster burning powders sometimes can also slug a soft bullet. too bad you cannot find a hollow base mold as that was also a cure for older OS barrels. The Lee hollow base 45-70 mold is a good one for Trap Door shooters dealing with various bore sizes. Hollow base bullets were also developed for some older revolver cartridges.
Before spending a lot of money try things to see if they work. If something works don't fix it.

DEP

[w30wcf]

The rifling is quite washed out, very faint. The muzzle seems OK, beveled a little uniformly.
I beagled my mold and got the boolits up over .260. I was thinking maybe try 3-4 grains of trail boss, unsized, no gas check. Would need another sizer to apply the GC and keep them big. Think I should pick up a NOE expander plug so as to open up the neck a little more?

Edit: slugged the bore. Gun is basically smooth bore, barely detectable rifling on the slug, and tight, .253" at the widest. Hmmm...hopeless?

Maybe not hopeless. What bullet / alloy are you using?

If you are using a lubrisizer, you could run the bullet in just far enough to size the g.c. to .260".

You could open the neck entrance using a larger pointed bullet going in nose first just a bit.
Will a .260" bullet fit into a fired case? If not, I would suggest seating one into a fired case to be sure it chambered ok before loading a number of cartridges.

If you have some H322 / H335 / BLC2 I would suggest trying a capacity load of these slower powders.

w30wcf

[Boolseye]

Many thanks for the tips. Forwarded to dad, the gun is back in his hands for now.

[castalott]

Just a thought.....beg, borrow or steal (jus' kidding) a few jacketed bullets to try....see if they do the same....

[pietro]

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If all else fails, before spending the $$$ to get the barrel re-bored/re-rifled to .32cal, I would run a 3/8" drillbit down the bore from the muzzle end, for a few inches & re-crown the new/internal/recessed end of the rifling - to find out if you can still get it to shoot more accurately (& w/o keyholes).


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[Boolseye]

Sounds good, guys. Yeah, it did the same with jacketed.

[castalott]

well....I guess your options are endless now...just takes money. If it were mine. I would either add a custom cast friendly barrel in 25-20 or 32-20. Or have that one rebored. First though, I would have a good leversmith check the action to be sure it's worth rebore....

Good Luck & let us know how it turns out...

Dale

[Ballistics in Scotland]

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If all else fails, before spending the $$$ to get the barrel re-bored/re-rifled to .32cal, I would run a 3/8" drillbit down the bore from the muzzle end, for a few inches & re-crown the new/internal/recessed end of the rifling - to find out if you can still get it to shoot more accurately (& w/o keyholes).


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Counterboring the barrel like that is a possible cure for widening near the muzzle, but I wouldn't do it with a plain drill bit. You may still find you have to rebore or line the barrel, and for both of those you need it to start with the sort of alignment for which you need some sort of piloted tool.

[Boolseye]

I believe my old man is in consultation with a reliner. I will let you know what transpires.

[LtFrankDrebbin]

The rifling is quite washed out, very faint. The muzzle seems OK, beveled a little uniformly.
I beagled my mold and got the boolits up over .260. I was thinking maybe try 3-4 grains of trail boss, unsized, no gas check. Would need another sizer to apply the GC and keep them big. Think I should pick up a NOE expander plug so as to open up the neck a little more?

Edit: slugged the bore. Gun is basically smooth bore, barely detectable rifling on the slug, and tight, .253" at the widest. Hmmm...hopeless?

Tight? .253 at the widest?? Smooth bore???
Hang on if I'm not mistaken here, that sounds to me she's jam packed full of crud still. Barrel should be bored at .250 and the groves cut you should get the optimum .257. Then the good old +/- .002 for tool tolerance.

If it were shot out should it not be measuring at the least .257 + and smooth?

[Boolseye]

Good point. However, hammering a lubed oversized slug should have cleaned it out some (I have seen that procedure leave a mirror in its wake). Also did some serious scrubbing with shooters choice and a 30 cal bronze brush...its pretty pitted in there, too. Maybe I'll have another go at it. Could it just be pitting and corrosion that have reduced the bore?

[w30wcf]

I was thinking the same thing ..... .253" is definitely too small.

A brass brush typically won't remove leading much at all. I would try using the correct 25 caliber brush and wrapping some fine steel wool around it. After you run that back and forth in the bore a few times, there will be some lead flecks on the steel wool if there is any. I have read that Chore Boy scrubber for pots and pans will also work but I have no experience with it.

What jacketed bullet did you try? I find that the standard 86 gr bullet is marginally stable at standard .25-20 velocities but the 75 gr Speer works really well. I could send you 10 of those to try if you are interested in doing that.

w30wcf

[Boolseye]

OK, sounds good. More work ahead. I will PM re. those 75 grainers if my dad doesn't have any, much obliged.

[Ballistics in Scotland]

I was assuming, it now sounds incorrectly, that that .253 was the land diameter, which would be large but not doom-laden. Whatever make the bore smaller or larger than standard is unlikely to be the same all along, so determinging the diameters at various points along its length would probably give some information.

[Boolseye]

Yes, to clarify, .253" groove diameter. To the extent that grooves exist at all.

[1Hawkeye]

Boolseye, it might be time to get the elbow grease. .253 is a good number it might be leading. Did you remove the bolt and look at the bore from the chamber end? With all the scrubbing you have done if a patch with hoppies on it is still coming out black then it is leaded up still. Try some four ought steel wool wrapped around a jag cleaning from breach to muzzle and see what comes out. 25-20's were also known for erosion from corrosive primers but this will be at the breach end of the barrel. I went through all this about 20 years ago with a 92 Winchester in the same caliber and wound up having it re lined by Redman's rifling & reboring. Good luck keep us posted.

[Boolseye]

will do.

[pietro]

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I've found that (for me) the electronic Outers Foul Out III bore cleaner will dissolve any lead in the bore.

(in use, one end of the bbl is plugged, the electrolyte poured into the bore, and the electrode/rod immersed in the bore overnite, after it's plugged in to 110V AC.

https://www.midwayusa.com/product/243419/outers-foul-out-3-bore-cleaning-system


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[Boolseye]

I reefed on it for awhile with steel wool–no appreciable changes. It'll go off to the re-liners eventually.
I'll let y'all know what transpires, may be a few months yet.
4-22-16 update: It's at Redman's. Should be done mid-july.