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.30/40 to 7.62x54R

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.30/40 to 7.62x54R
kcraig514 Offline
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#1
02-05-2014, 09:01 PM
Hey Guys,
I'm new here and would like some feedback on a project I've been thinking about. I've got a Springfield Model 1898 rifle chambered in .30/40 Krag. The barrel has been replaced and the stock was butchered in the process ("sporterized") killing any value. I was thinking about rechambering it, but the Russian round is about .003 in. bigger than the Krag. I was going to get a barrel blank from Green Mountain Barrels and rebarrel it. The rounds are close enough to the same size to work in the action. The 7.62 is actually only .050 in. shorter than the Krag. My concern is with the bolt. I can't find any info on pressures. I don't want the lug (single) to break and take a bolt in the face. Energy is similar with the 7.62 @ 2677ft/lb and the Krag @ 2209ft/lbs. Is this enough difference to matter? I've been a machinist for over 25 yrs but want to get into gunsmithing. This is the point of this project is to gain some experience. Whatcha think?
Keith
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Highpower Online
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#2
02-06-2014, 01:39 AM (This post was last modified: 02-06-2014, 01:40 AM by Highpower.)
Welcome to the forum. Welcome

My Lee manual puts the .30-40 at approx 38,000 PSI and the 7.62x54R at approx 50,000. I'm sure those are sporting / SAAMI figures. I own several Mosin-Nagants and shoot milsurp ammo. I would venture a guess that Bulgarian "yellow tip" is probably closer to 70,000 PSI judging by the recoil and fireball that erupts from the muzzle. Blink
Willie
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stevec Offline
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#3
02-06-2014, 06:38 AM
Knowing less than nothing about gunsmithing and little about guns my curiosity begs "why the change from 30/40 Krag to 7.62?" 17428
Busy Bee 12-36 lathe, Busy Bee Mill drill, Busy Bee 4x6 bandsaw, Homemade 9x17 bandsaw, Ad infinitum.
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Highpower Online
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#4
02-06-2014, 12:19 PM
.30/40 Krag ammunition is hard to find these days and very expensive if you do find any. The Russian round is available by the truck load if you don't mind shooting corrosive military ammunition. It USED to be cheap but like all other ammunition, costs have skyrocketed. Commercial sporting 7.62x54R is still half the cost of the .30/40 round though. The problem is the Krag action with only one bolt lug was not built to handle the higher pressure of the 7.62 Russian ammunition.

I have a similar situation with my Ishapore 2A rifle. Even though it was designed to shoot 7.62 NATO ammunition, shooting commercial .308 Win ammunition in these rifles has lead to some catastrophic failures due to the increased pressures. Personally I believe that even modern 7.62 NATO ammunition in that gun is running on the ragged edge of safety, and I hand load my own ammo to lower levels. I'm not a big fan of touching off pipe bombs right in front of my face. But that's just me. Tongue
Willie
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kcraig514 Offline
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#5
02-06-2014, 04:46 PM
12,000 psi increase....I think I better leave this one alone!
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Highpower Online
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#6
02-06-2014, 10:25 PM
Well at least you can still get brass for it and roll your own.
https://www.grafs.com/retail/catalog/pro...ctId/16674

I'm sad to say a Krag is one item missing from my accumulation of small arms. I've never run across a nice one I could afford. Sad
Willie
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Old Iron Offline
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#7
02-18-2014, 10:45 PM
I buy a lot of components from grafs, Great Company to deal with.
Paul
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#8
02-19-2014, 07:07 AM
(02-18-2014, 10:45 PM)Old Iron` Wrote: I buy a lot of components from grafs, Great Company to deal with.
Paul

I agree. Nice people to talk to as well. I used to work right down the road from one of their stores. Made it all too convenient for me to empty my wallet often. Rolleyes
Willie
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