Ordered 16lbs of MP 842 Powder (similar to WC 842). Need good source of starting load data.

[arakboss]

I finally had the opportunity to test out the rounds I loaded from 20gr to 22gr. None of them showed any pressure signs and I didn't get any bullets stuck in the barrel. The bad news is none of them locked the bolt back on the empty pmag. I loaded one round at a time to see if they would lock the bolt back. Next step is to load some at 22.5gr and maybe 23gr and see if I can get bolt lock back.

It was the first time firing this home built rifle and I ran some factory loads through it first to test the function of the rifle. The bolt locked back on the factory rounds.

I am going to play around with this MP 842 again this weekend. Stay tuned.

 

[arakboss]

I did some more experimenting with the MP842 powder, trying to achieve miminum load for bolt lock back. Here are my notes.

Tried loads with 55gr bullet and 22.5 and 23gr of mp842

Also tried 62gr bullets with powder amounts shown in photo. All 62gr loads locked bolt back. Both 55gr loads with 22.5 and 23gr of powder locked bolt back. I retested previous rounds and 21.5 and 22gr 55gr loads locked bolt back. Primers all look pretty good.



Looking at bottom row from left to right, cases 1,2,3,4, and 6 were the 62gr loads. Charge weights were 20, 20.5, 21, 21.5 and 22 grains for the 62gr bullets.


Cases 5 and 7 were the 55gr loads. Charge weights for these bullets were 22.5 and 23 grains.

 

[DizzyJ]

I did some more experimenting with the MP842 powder, trying to achieve miminum load for bolt lock back. Here are my notes.

Tried loads with 55gr bullet and 22.5 and 23gr of mp842

Also tried 62gr bullets with powder amounts shown in photo. All 62gr loads locked bolt back. Both 55gr loads with 22.5 and 23gr of powder locked bolt back. I retested previous rounds and 21.5 and 22gr 55gr loads locked bolt back. Primers all look pretty good.

View attachment 1234503

Looking at bottom row from left to right, cases 1,2,3,4, and 6 were the 62gr loads. Charge weights were 20, 20.5, 21, 21.5 and 22 grains for the 62gr bullets.


Cases 5 and 7 were the 55gr loads. Charge weights for these bullets were 22.5 and 23 grains.

How was velocity and accuracy?

 

[arakboss]

How was velocity and accuracy?

Sorry no chrono and I was only shooting at target 20ft away. I was just testing for bolt lock back.