Pressure Excursion??

[Festus]

I've been handloading nearly forty years and have done some stupid things but never have experienced a pressure excursion until last friday. At least I think that's what it was.

I had been shooting the 154 gr. Hornady IB in my 7mm STW with WW brass, F215GM primers, RL-25, starting @ 79 gr. and going up to 82gr. Pressures seemed ok with all of these but accuracy wasn't what I wanted. Keeping all other components the same, I switched to the Barnes TSX 160 gr. FB and cut my starting load to 77 gr. I'm seated well off the lands and cases are trimmed to within specs. My first shot with the Barnes TSX gave me a stiff bolt lift, shiny ejector mark and blown primer. I packed it up and went home to check my data and codgitate. I'm still puzzled. This load should have been mild. I was shooting over a chronograph and the load clocked 3171 fps @ 15 ft. from the muzzle.

Any suggestions?

Thanks, Festus

 

[sewwhat89]

A 160 Barnes is as long or maybe a bit longer bearing surface as the 175s. If you are not using Barnes's manual, email them about the question, and they will get back to you promptly. I have had several questions with their bullets, and in one case, a guy went and ran some quick and dirty loads to give me an idea of what loads I could use. I was a few fps behind the velocities he gave me, but the loads were golden.

 

[Festus]

Thanks, I have sent emails to both Barnes and Alliant. Barnes has a warning on their website that they are getting inundated with emails and that a prompt response may take a few days. I have patience.

 

[Festus]

I've talked to Barnes and Sinclair and they don't believe this was a pressure excursion, just a hot load. Alliant did respond but wanted the lot # of the powder and when the purchase was made. I will probably hear from them again tomorrow. Barnes suggested cutting the charge by 2 to 4 gr. and checking results. I just don't know why RL-25 would burn this fast in this application. Guess I've got some bullets to pull. /ubbthreads/images/graemlins/confused.gif