30-40 Krag

[JeffreyDeGraff]

I’m not one to chase velocity in my reloading, but I find myself doing it with my 30-40 krag. I have a very accurate load with 180gr Sierra RN and IMR4831 @1900fps. The problem is that my barrel is short and I get 250-300fps less velocity than what the books say the load should get. A tech from Sierra told me that the 180gr RN has a thick jacket and to get reliable expansion, impact velocity should be above 2000fps.

Ive got some loads loaded up with IMR4831, AA4350, and western big game, trying to reach around 2100fps


JTD

[Flyeralan]

Not any help with that particular cartridge, although I had to work the same kind of issue years ago with my 7mm TCU in a 10" barreled Contender. Using a Sierra single shot pistol 130g bullet (no longer produced) I found a compressed load of H4895 that shot 1" groups at 100yds all day. I took it hunting in PA doe season to test it out. Had a doe walk under my tree and I was up 30 feet or so, my first shot brought almost no response from her. She moved a little and I took a second that put her down very quickly. When butchering I found both had broken a rib about 2" from the spine, one on each side. The first passed through without expanding and the 2nd expanded and wreaked total havoc in the boiler room. So, back to the bench to add more powder to a compressed load. When I reached a certain point of compression my groups went south badly, so I pulled the bullet out a little and added more powder until I was able to gain about 250-300 fps for that load. We won't discuss how much bullet was left in the case on my final load, lol. I still have some loaded today.

[JeffreyDeGraff]

Ive got the bullet seated a decent way out and I’m not at a compressed load yet. I am advancing with caution due to the one lug (prone to cracking) design of the krag Jorgensen action. Load data is all over the place for the 30-40 krag. I am 4gr of powder over according to one source, 2gr under according to another. All of my loads are within someone’s published load data, I will update this thread as I go.




JTD

[Flyeralan]

I understand why you are cautious, keep us up to date as you learn.

[JeffreyDeGraff]

I made it to the range today and made headway on my dilemma. I safely made it to 2125fps with IMR4831, 2110fps with western big game, and 2050fps with accurate 4350. No pressure signs at all, with any of them. My goal was to be over 2100fps so that I would have an impact velocity of 2000fps at 100yds, for the bullet to work properly. I won’t be shooting over 100yds with open sights and these old eyes. IMR4831 was the most accurate of the bunch, so I’m going to stick with it.


JTD

[Flyeralan]

Thanks for the update, glad you found something that meets your objectives.

[JeffreyDeGraff]

Thanks for the update, glad you found something that meets your objectives.

Now I need to shoot something with it to see how it does.


JTD