303 British and 30-40 Krag

[Naphtali]

The thread about inexpensive 303 British ammunition prompts a question. Does 303 British ammunition feed reliably in 30-40 Krag actions? I do not - repeat - DO NOT ask whether the ammunition is safe to shoot, regardless of a Krag's bore diameter. If it does feed and a Krag's bore is loose enough for 303's larger bullets, it has unsafe pressure for Krags.

My thought is more mudane. If 303 British ammunition feeds reliably, 303 brass could be necked and reformed (if necessary) for .308-inch bullets. And presto, the availability issue with finding 30-40 Krag ammunition disappears. While I have not measured the volume to neck of either case, I suspect differences are slight. And safe cast bullet loads would be easy to create.

[LAGS]

Post a thread on the Case reforming section.
But the case head rim diameter on the .303 is smaller than the Krag, and the Krag case is longer.
But anything is possible just to get the Krag shooting.

[retread]

I have recently sized 303 to 30-40 Krag and it worked really well. No problems at all. About a week after I did that I stumbled onto a 303 Mark IV that followed me home and after running the loaded 303 brass through the Krag I resized it back for the 303. Again, not a problem.

[NVcurmudgeon]

As a shooter of both .30/40 and .303 I have the luxury of having both cartridges with "proper" head stamps. As my .303 inventory of cases is generous and my .30/40 case inventory is less than 200, I can see that I may be forming Krags eventually. When that day comes, the rims of the .303 MODIFIED cases will have a notch made by a three cornered file. In addition, the Lyman 311299 bullets sized .311" will have no punch marks, and the Lyman 314299 bullets sized .314" will continue to have the exposed punch marks that they bear already. I'm dimensionally blessed in having a .309" groove Krag and two .303's with .314" grooves. These old military rifles were made in 1898, 1915, and 1943, so I can be comfortable with 1400 fps cast bullets.

[Der Gebirgsjager]

Interesting thread, as I also have and shoot both. Fortunately, having been at the game long before my hair turned gray, I've acquired ample amounts of both types of brass and haven't had to convert one to another. One word of caution, or maybe just an observation, both of these
rifle types are notorious for having out of spec headspace, and for stretching the cases just forward of the rims. I would think that shooting in one, let's say a Lee Enfield, and then converting the brass to shoot in Krag, and then doing so, might hasten case head separation. On the other hand, if you have sufficient brass and don't have to convert, dedicating a couple of boxes of brass to a particular rifle and then neck sizing only will make it go a long way. Just a thought. I really enjoy shooting mine, and think the above suggestion to keep the loads on the mild side is good advice. Easier on the rifle and the brass.

[KCSO]

Actually 30-40 is just enough bigger in the rim area that it makes wonderful 303 when necked up and trimmed. The bigger 30-40 fills the 303 chamer better than factory ammo and lasts longer and doesn't split as easy.

[fgd135]

Fwiw, I've been resizing .303 brass with a .30/40 full length die and reloading them for a few years now--shooting light and moderate cast bullet loads. The brass feeds, extracts and ejects from my 1896 infantry rifle flawlessly. I've not noticed any erosion problems in the chamber, either.
I just neck size those cases afterwards.
Based on my experience with shooting hundreds of resized .303-.30/40 cases, I would not hesitate to use them. As usual ymmv.

[Naphtali]

The consensus appears to find nothing terrible about the idea. I think the reason it could work blandly and uneventfully is that these similar cases headspace on their rims. That the 303 British is shorter and somewhat "blown out" compared with 30-40 brass would translate to erosion where it would not be particularly harmful - unless the shooter, after shooting several hundred short cases, decided to revert to 30-40 brass. I suspect the outcome would be similar to shooting heavier 45 Colt loads in a 454, then using 454 brass.

[Idaho Sharpshooter]

Note to all: Before you buy anything, make sure you can buy at least 500 new cases for it somewhere. Bargain rifles are not, if you have to spend more than you paid for the rifle to obtain 200 new pieces of brass or a hundred rounds of factory ammunition.

Exception to this; anything bigger than a 375 H&H. You sit down, like I did at the range one sunny afternoon with a Case-Gard 100 full of full house 416 Rigby reloads I had concocted; and about thirty rounds from the bench and you are ready to go home and do something fun, like mow the yard...

[303Guy]

and about thirty rounds from the bench and you are ready to go home and do something fun, like mow the yard...

I'm not into recoil so much. A 22 is a bit too anemic though.

[N4AUD]

I've been going the other way for a while now- .30-40 to .303 British. I've got a pile of Krag brass and nothing to shoot it in, so I convert it to .303. Works great.

[303Guy]

Just one question, why would a shorter neck cause erosion when the full length neck does not? The mouth does not reach the end of the chamber anyway.

[fgd135]

Just one question, why would a shorter neck cause erosion when the full length neck does not? The mouth does not reach the end of the chamber anyway.

The difference is that firing a case significantly shorter than the SAAMI oal could possibly cause erosion in the chamber neck beyond the case, instead of just out in the leade...perhaps causing regular length cartridges to have difficulty chambering properly. Or just possibly leading could build up at the end of the chamber neck and cause jamming or excess pressures with regular oal cartridges. Always something to consider, and it is worthwhile to carefully examine your rifle after using short-necked cartridges.

[303Guy]

I have had build up in front of the case mouth in a 22 rf revolver when using BB caps that prevented chambering of LR cartridges. My Dad told of mixing shorts and LR's in his Mauser rifle (which I now posses) and said he found it took several shots before the LR's grouped properly again. I'm now wondering whether inconsistent case length could cause pressure problems due to pinching on the longer necks?