Krag 30-40 Action, Conversion to other calibers possible?

Squaregrouper · Aug 8, 2018

Cruacious said:
True that. But I doubt anyone put a Krag into 30-30. If they did, I want it.

I now have the urge to trick out an already Bubba'ed Krag rifle. Changing calibers is well beyond my skillset. Unless...
6.5 Kragmore shooting 100gr projectiles with low powder charges. You have until Thanksgiving to complete the task.

iH8DemLibz · Aug 8, 2018

Just measured and ran some .303 British through the Krag.

The .303 has the EXACT same rim diameter as the .30-40. The .303 feeds from the magazine. Goes all the way into the chamber. BUT...won't close on the round. Obviously. .100 inches shy of closing. Ejects fine too.

Looks like a .30-40 chamber could be reamed to .303 British and all would be fine from a mechanical standpoint.

Question is: Can a .311 bullet be run through a .308 bore safely? I'm certain cast lead bullets would compress and be perfectly safe. Copper jacketed???

Chamber pressure would have to be looked at too.

PS: Oops..... Looks like shoulder diameters could be a problem. The .30-40 shoulder diameter is .015 bigger than the .303 British shoulder. So a .303 chamber reamer wouldn't clean up the .30-40 chamber completely. Either a new barrel/chamber would be needed. Or face off a Krag barrel/chamber and finish ream to .303.

TargetGrade · Aug 8, 2018

iH8DemLibz said:
Just measured and ran some .303 British through the Krag.

The .303 has the EXACT same rim diameter as the .30-40. The .303 feeds from the magazine. Goes all the way into the chamber. BUT...won't close on the round. Obviously. .100 inches shy of closing. Ejects fine too.

Looks like a .30-40 chamber could be reamed to .303 British and all would be fine from a mechanical standpoint.

Question is: Can a .311 bullet be run through a .308 bore safely? Chamber pressure would have to be looked at too.

Bigger question... why make it a 303 other than to be different? From a ballistic standpoint... they're almost identical. If one were suicidal one could load the 30/40 almost parallel to .308.

iH8DemLibz · Aug 8, 2018

TargetGrade said:
Bigger question... why make it a 303 other than to be different? From a ballistic standpoint... they're almost identical. If one were suicidal one could load the 30/40 almost parallel to .308.

Just trying to help the OP with his cartridges commonly available problem/solution.

Plus.....This stuff is fun fun fun.

TargetGrade · Aug 8, 2018

iH8DemLibz said:
Just trying to help the OP with his cartridges commonly available problem/solution.

Plus.....This stuff is fun fun fun.

Hard to put a price on fun if one likes it I guess.

In reality it's like putting a 302 in a 66 Vette or 327 in a Boss 302 Mustang.

Cruacious · Aug 8, 2018

Actually the .303 idea sounds like a good idea for reloading as I could form the cases into 30-40 brass it seems. I also happen to have a lot of .303 sitting around so... Ideas!

iH8DemLibz · Aug 8, 2018

If you're going to reload, might as well reload .30-40.

I had your handy little tacti-cool Krag already built in my head.

Now bust out the hacksaw and files and commence to whittlin'.

Cruacious · Aug 8, 2018

Just a note, .303 pressure maximum is well above what a Krag receiver can handle. 30-30 is within the pressure maximum specifications and well below the breaking point. 6.5 is doable, but would have to be light loaded as it's still above what the receiver was designed for with 30-40 (as the Norwegians used a lighter loaded 6.5 apparently).

Now I just need a Krag to play with and a lot of different ammo types to choose from. I swear I am going to find a way to make this work!

Biggfoot44 · Aug 8, 2018

If you are looking for * semi- common ctg, that can be fired in Krag using factory ammo * , not really an possibilities .

If you accept handloading only , with probably some case forming also , then you've got possibilities .

Spitballing within my personal druthers , IF the bbl was externally ok , I would have it rebored to .35 ( could do .338 if you wanted ) , and contemplate using .303 brass .

BUT if you really, really wanted a .30-30 Krag , you would want to think Norwegian, not US . The 6.5x55 rim is .480 , and the bolt face could easily be opened up for .30-30 size ( .506 ) .

I thought about using just a Norwegian bolt in a US rifle , but the chamber issues discussed above would require a new bbl , whereas a 6.5 could be bored out .

( Is it too late to again express admiration for the .30-40 as a cartridge ? )

TargetGrade · Aug 8, 2018

Biggfoot44 said:
( Is it too late to again express admiration for the .30-40 as a cartridge ? )

I like it, the rap on it was TR supposedly claimed they were outgunned going up San Juan Hill by the 7x57. Not sure I buy into that. The Mauser action was far superior and much faster with a stripper than a box. Now enter the 30 03... and the rest is history.

The 30/40 in the Krag almost has no noticeable recoil... to me anyway. I find it very comfortable to shot.

Hell it was good enough for Lee Marvin to go hunting for Charles Bronson.

Cruacious · Aug 9, 2018

Biggfoot44 said:
If you are looking for * semi- common ctg, that can be fired in Krag using factory ammo * , not really an possibilities .

If you accept handloading only , with probably some case forming also , then you've got possibilities .

Spitballing within my personal druthers , IF the bbl was externally ok , I would have it rebored to .35 ( could do .338 if you wanted ) , and contemplate using .303 brass .

BUT if you really, really wanted a .30-30 Krag , you would want to think Norwegian, not US . The 6.5x55 rim is .480 , and the bolt face could easily be opened up for .30-30 size ( .506 ) .

I thought about using just a Norwegian bolt in a US rifle , but the chamber issues discussed above would require a new bbl , whereas a 6.5 could be bored out .

( Is it too late to again express admiration for the .30-40 as a cartridge ? )

What about a Danish Krag?

Biggfoot44 · Aug 9, 2018

For your desired cartridge conversion , a Danish would be even worse . It is in 8x56R , which has a .579 rim dia .

You would be looking for somthing in 6.5x55 for your purposes .

Cruacious · Aug 9, 2018

Fair point. Finding a Norweigan though is a real PITA. Finding a cheap Bubba'd one is likely even worse. No easy solutions here I bet.

iH8DemLibz · Aug 9, 2018

Another piece of the puzzle located.

Frankenkrag.

Doco Overboard · Aug 9, 2018

Thats a thing of beauty

, Im going to build a Bubba krag with a forward mounted scope I think. Or maybe something slightly more traditional.
Need to find a stock to re-purpose. Maybe some chopped up 1903 timber will work.
I'm sticking with 30/40.

Cruacious · Aug 10, 2018

Well, I've decided to officially chase-down the Norwegian. The problem is... there's none to be found! This frankly sucks.

Looks like grabbing a Bubba'd 30/40 Krag and figuring it out from there might be a better idea.

iH8DemLibz · Aug 10, 2018

How are you planning on overcoming the .30-30 rim/Krag bolt body diameter/feeding problem?

Cruacious · Aug 10, 2018

I might actually mill the bolt out and set a new barrel a bit further back. Changing the feed ramp angle would also be beneficial probably. It will likely need serious machining to get it right as well. This won't be a job for hand tools, this will be more of a job for a machine shop and possibly a CNC machine. Also, the extractor can be lowered with some machining.

It may also be possible to do a slight redesign on the bolt at the same time to reinforce it (as I believe the bolt is the weakest link of a Krag). I may be getting into serious gunsmith concept here though, but that's just how I am sometimes with my ideas. If it isn't broken, why can't I make it better?

Also, I'm not married to the idea of 30-30 WCF entirely. I could also go for 30-06 with a light load, etc.

noahhh · Aug 14, 2018

Do not go sticking a .30-06 in a U.S. Krag! Even if you are conscientious and feed it light loads sure as heck some dumb schmuck will come along eventually and jack up his world by firing modern high pressure loads in it.

I have played with Krags for 50 years and have converted a few to odd ball cartridges. Never ever have I been successful in getting anything but a .30-40 cartridge to feed reliably. Ever. It pretty much becomes a single shot when different calibers are applied. Bank on that. Save your sanity for projects that have a hope of being successful. The advise others have offered re: just sticking with the original cartridge is spot on. There really is nothing wrong with a .30-40 - it''ll kill anything that moves on the North American continent and is so seldom seen these days as to have become an exotic in its own right anymore. Brass is easy to find.

As for the one locking lug, that's it. Don't try lapping that lug so that the safety lug bears firmly too. What you accomplish by doing that is wearing through the case hardening on the lug/lug seat. Krag bolts don't blow out the back of the receiver when they fail, the safety lug is beefy and prevents that. Krag bolt lugs can be found to be cracked though- inspect carefully before using.

Here's one that is about as oddball a Krag that you'll ever see. Single shot, naturally. Chambered for .22 Maximum Lovell (Google it), Pacific double set triggers, bolt face altered and extractor hook extended to accommodate the small rim diameter. Bug hole shooter.

iH8DemLibz · Aug 14, 2018

Thanks for the write-up and pic.

Nice rifle.

Krag 30-40 Action, Conversion to other calibers possible?

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