oversize bore in '93 Marlin.

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  • Last Post 03 March 2019
loophole posted this 27 February 2019

I have bought two Marlin '93 rifles in 32-40 cal.  The first one with a bore that looks like it ought to shoot keyholed bullets--new Hornaday case, 14 gr 4227--with .321" dia bullets and also Winchester jacketed loads at 50 yds. Slugged both bores, measured .324 grove dia.

Attempts to make cerrosafe chamber cast unsuccessful.  Two casts exactly following Brownell's direction, neither would be pushed out of the bore even with a long brass rod and a hammer.  Each time I melted out the cerrosafe--fortunately an 1875 watt heat gun melted the stuff.  Acts like it was soldered into the chamber.  I decided a chamber cast will not work, so I made some paperpatched bullets which show that the chamber will accept a .326 bullet. 

sized bullets, both grease-groved and paper patched and loaded them into carefully neck expanded cases.  Cases will not chamber because with the oversize bullet the neck is too big dia for the chamber.  Using a sizer die as a taper crimp die, reduced the dia of the neck to SAAMI specs and the cases chambered perfectly.  Of course the crimp also resizes the bullet.

I now see that the bullet which fills the chamber ahead of the case is oversize, but the chamber neck is too small to allow the oversize bullet load to chamber.  Weather has not permitted me to get to the range and my new loads, but assuming they don't shoot accurately, do I have any alternative to honing the neck area of the chamber and a sizing die to accept a larger bullet?

since I have two rifles with the same bore and chamber dimensions I assume Marlin used these on its 32-40 rifles.  How did deer hunters in those days shoot commercial ammo in these guns ?

Steve K 

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M3 Mitch posted this 27 February 2019

My guess, and it's just a guess, is that the chamber neck is undersized for the bore.  Possibly a good gunsmith can lap it out or otherwise increase the chamber neck diameter.  If you can determine when your rifle was made, I have heard that the last few months of Connecticut manufacture and the first of New York manufacture were problematic. 

I'm not coming up with any cheap and cheerful DIY approaches, but that does not mean they don't exist, just that I don't know about them.

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RicinYakima posted this 27 February 2019

The ammo they were made for used 30/1 alloy swaged bullets and the cartridge was loaded with black powder. On firing the bullet obturated up to fill the throat. That method still works, but not many want to do that anymore. FWIW

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Ed Harris posted this 27 February 2019

A heeled, RWS stop-ring type bullet for the 8.15x46R might work

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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45 2.1 posted this 27 February 2019

I have bought two Marlin '93 rifles in 32-40 cal. .................the chamber neck is too small to allow the oversize bullet load to chamber.  This is common in this era of rifle with throat and barrel too large for the chamber... soft bullets or PP allowed good accuracy ......................... do I have any alternative to honing the neck area of the chamber and a sizing die to accept a larger bullet?  Yes, you do. Since you are already paper patching, try the Lyman 319247 cast of pure to not over 40:1 lead/tin patched so your cartridge will chamber. This will let you shoot fixed cartridges with accuracy and will be OK to hunt with. The patched bullet will bump up fine. 

Steve K 

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loophole posted this 28 February 2019

I have the  319247 mold backordered--everybody seems to be out of stock.  Many years ago Ken Waters wrote a series of articles in the Handloader, in which he tried this method with 45-70 rounds.  He reported that he could not get any accuracy, and I never tried it because I never had a rifle with a bore/chamber like my Marlin.  I will try it.  I do not want to have the chamber neck reamed larger if I don't have to.  How common is this problem with 100+ year old rifles?

Thanks again for your responses.

Steve K 

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Wineman posted this 28 February 2019

I had a 94 Winchester in 38-55 from my Father in Law with an octagon barrel and half magazine. The SN dated it to 1906. Bore was sewer pipe dark and several cleaning cycles did not improve it. With Winchester factory jacketed it keyholed at 10 yards. I never slugged the bore or tried any fatter cast. Somebody wanted it more than I did so it got a new home.

Dave

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Ken Campbell Iowa posted this 28 February 2019

if the problem is that the necessary larger bullets make the brass neck too tight in the chamber, maybe you can thin the necks ... neck turning, inside reaming, or just tapering the inside as necessary, a handymans $5 taper reamer might do to gain a 1/10 inch or so.

ken

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Rich/WIS posted this 28 February 2019

Would cleaning up the chambers with a correct dimension chamber reamer help?

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RicinYakima posted this 28 February 2019

" How common is this problem with 100+ year old rifles?"

Very common, especially in 1873 Winchester 44 WCF. When cowboy shooting first started 30years ago, these were very common around here. That is what the guys found out what you had to do to make them shoot. Some used Unique powder charges, but to work had to be hotter than the BP ones.

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45 2.1 posted this 28 February 2019

Many years ago Ken Waters wrote a series of articles in the Handloader, in which he tried this method with 45-70 rounds.  He reported that he could not get any accuracy, and I never tried it because I never had a rifle with a bore/chamber like my Marlin.  I will try it.  I do not want to have the chamber neck reamed larger if I don't have to. 

Most people try too hard of a bullet. You need to go 25:1 or softer with naked bullets. With PP you can use pure lead up to about 30:1 depending on load. In the larger calibers a hollow base bullet works wonders as well as PP'ing, but you aren't going to find a reasonable HB with the 32.

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R. Dupraz posted this 28 February 2019

This is a common and unique problem to the Marlin 336 Cowboy 38-55 rifles that they introduced some time in the eighties. They must have checked back in their archives and used those 90 yr. old spec's when chambering the new cowboys. The fix was to open up the chamber neck with a special reamer after which they shot very well with cast bullets

When I got mine, I also bought a couple of boxes of  factory Win. 260 grain jacketed, just to initially shoot it and get  cases to reload. And that Marlin would dang near stack those factory jacketed on top of each other at fifty yards. But how could this be after it's dismal failure with cast.

After sawing one of those factory jacketed bullets in half, it was found that they weren't jacketed at all but copper plated soft lead. 

 

R.

 

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loophole posted this 28 February 2019

Well boys the mold is on backorder and I just ordered 5 lbs of 1-30 nuggets from Rotometals. I have a large supply of pure lead, but I always had difficulty casting pure lead into anything but roundballs.  I can get better casting out of 50% nuggets and 50% pure lead if I want something real soft for paperpatched bullets.  I have a 336 rifle in 38-55 with ballard barrel.  I have had very little chance to shoot it and never took time to work up a load for it.  I'll check and see if it has the old oversize bore dimensions.  I may have to try the same method as with the 32-40.

I did not try neck turning the cases.  I used to do that with varmint rifles, but I'm think the 32-40 case has too thin a neck to allow that here.

Steve k  

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M3 Mitch posted this 28 February 2019

An outfit that advertises in Rifle and Handloader, Turnbull Restorations, might be worth checking into for being able to correct that chamber.  If you really don't want to open the chamber up some, which is what I would do, probably Ed's idea of a heeled bullet is the "best way out of the woods" so to speak.

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RicinYakima posted this 01 March 2019

Another alternative is to buy an Ideal mould from the same period. I see them for sale on eBay every couple of weeks. Most are stamped on the cut-off ".32 - 165 M.". They are all plain base and made for only lead tin alloy.

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loophole posted this 03 March 2019

Once again I want to thank you for your suggestions.  We finally had a beautiful mountain 60deg, sunny day and I went to the range.  I did not get to do nearly as much shooting as I would like, but I did confirm  that those of you who explained about soft lead bullets and black powder having allowed early rifles to shoot accurately are right.  Since I would like to shoot some of my old guns as they were designed to be shot, I don't want to open up the chamber on my Marlin 1893 until I get the mold and try 30-1 bullets.  Black powder is easier to clean in the Marlin than smokeless, since it is so easy to push the fowling out the muzzle.

Some things which may be of interest related to this is that my 44-1/2 Stevens 38-55 has a more modern chamber.  It shot bullets which were loaded for a Browning highwall which has a green mountain 38-55 barrel into 3shot cloverleaves at 50 yards as soon as we got the tang sight set.  17gr 5744, 245gr Meister bullet.  My Marlin 1893 in 30-30 shot 165 gr 309" dia bullets into recognizable groups, but I took too much time getting the tang sight adjusted to shoot seriously for group. A Win Mod 94 which was made in 1895 in 38-55 also shot nice groups with no sign of keyholing at 50 yards, but it was no fair test of accuracy because I have no tang sight on it and it is almost impossible for me to see the bead in the v in the barrel sight. 

If anyone knows which of these old rifles were made with oversize bores, please let us know how to identify them. I've found that many nice old rifles are listed on the 'net by owners who never shot them and know nothing about loading for them.

Steve k 

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