Reloading 7.62x51 has me scratching my head

[NWSharpshooter]

You are going to find that with mag primers the powder will be different. I'll also say again that 37 grains is a serious undercharge and you are running the risk of detonation. FPS is irrelevant, it may be a dangerous load. Start over.

And you are saying it is a serious undercharge based on what reloading data? What is the minimum load for a 150gr bullet using CCI #34s and IMR 4895? It is 5grs under minimum using a CCI 200 primer, but that is not the primer I am using.


Do you have any data to support the undercharge detonation theory. I will admit I have not looked into it in over 10 years, but last I looked it was a theory that no one had been able to replicate in a controlled environment.

 

[mojoween]

The problem is with the magnum primer. The Military primer and the 250 ARE NOT the same. You should be using standard large rifle primers or military. The magnum primers can make a load designed for standard primers dangerously hot, which is what you experienced. Start over using the correct primer for the load data.

BTW, you should never load less than the starting load. It can cause a "detonation", rather than a controlled burn, that will spike pressures way over the top. Too little powder can be just as dangerous as too much.

Just so you know, the only real difference between a regular primer and a military primer is that the cup on a military primer is stronger to prevent slam fires.

I agree with this. I load 45gr IMR4895 with great results and have had no issues. I think the magnum primer is your problem.

 

[NWSharpshooter]

I agree with this. I load 45gr IMR4895 with great results and have had no issues. I think the magnum primer is your problem.

Read back two post. CCI confirmed that the primers are the same. You load 45gr under what bullet, in what brass, and for what gun? Lots of variables here.

 

[NWSharpshooter]

You are going to find that with mag primers the powder will be different. I'll also say again that 37 grains is a serious undercharge and you are running the risk of detonation. FPS is irrelevant, it may be a dangerous load. Start over.

Hodgdon has load data on their page for "youth loads" that talk about reducing power by 60% for 4895 loads and talks about how 4895 is the ideal powder for reduced power loads.

By taking the maximum charges listed in our Annual Manual with any given cartridge and multiplying it by 60%, the shooter can create a 1500 to 2100 fps load, depending on the bullet weight shown. This works only where H4895 is listed. Do not use H4895 in a cartridge where it has not been shown.

i do realize that IMR 4895 is ever so slightly hotter than H4895, but H4895 is based of IMR and both are very close to one another. Even if there was evidence to support light powder detonation, I'm not too concerned with it using 4895, especially when my light load still fills 80% of the case. If I was loaded belted magnum loads with a really light load of slow burning powder I could possibly see it happening, but not with 4895 in a 308 case.

 

[NWSharpshooter]

Bump

 

[NWSharpshooter]

I should clarify. I understand that the 250 magnum primers increase pressure which is why my starting load was too hot. What I looking for is load data that corresponds with the use of the #34 primer. I have yet to find anything other than notes telling me to decrease by about a grain. This is not helpful as I believe a max load "decreased by a grain" would destroy my gun.

 

[Bear44]

Look for loads for the 7.62X51 rather than the 308 Win.

As for the rest of it, whatever.

 

[NWSharpshooter]

Look for loads for the 7.62X51 rather than the 308 Win.As for the rest of it, whatever.

Now you see why it has me scratching my head.

 

[Springfield 1911]

Hodgdon has load data on their page for "youth loads" that talk about reducing power by 60% for 4895 loads and talks about how 4895 is the ideal powder for reduced power loads.




i do realize that IMR 4895 is ever so slightly hotter than H4895, but H4895 is based of IMR and both are very close to one another. Even if there was evidence to support light powder detonation, I'm not too concerned with it using 4895, especially when my light load still fills 80% of the case. If I was loaded belted magnum loads with a really light load of slow burning powder I could possibly see it happening, but not with 4895 in a 308 case.

H4895 is a coated powder, IMR4895 is not. I would not assume anything based on how one does or does not perform. Both powders, however, are great in the 308WIN.

 

[Springfield 1911]

H4895 is a coated powder, IMR4895 is not. I would not assume anything based on how one does or does not perform. Both powders, however, are great in the 308WIN.

Same thing with book loads and Mag primers, they only work when one was made for the other. I would start over with the LR primer. I do have some 308WIN loads that use mag primers but none in a semiauto.