My first neck separation

[towerofpower93]

My question is going to be more oriented to shooting a suppressed and SBR'd PS90, but handlods were used as well so may a son well put it here.

BL: was out testing a couple new mags yesterday and got my first neck separation at round ~90. Here's the load data:

1 x fired brass resized to freefall out of my clean PS90 chamber, trimmed to proper length
40gr VMAX
5.4gr Win Auto Comp
Rem 7.5 SRP
OAL: 1.585"

This nets me 2150-2250fps in my SBR'd PS90 running a recored SFN-57 made user serviceable.

I'm guessing this was a case of too much back pressure from the suppressor combined with a hot chamber. I fired the two mags doing quick strings of 4-7 rounds on steel at 50yds. I was testing the new mags to ensure function, so wanted to go a little faster than a slow seated firing pace.

So, assuming my assumption is correct in that the back pressure from the can caused the separation, is there a way to slow down the bolt (stronger springs or added mass) or does anyone see issue with my load?

Welcome any and all input. This load has served me well in this rifle over many hundreds of rounds without ever giving me a separation.

Thanks

[748]

Cool some one else who sees it too.
It looks like my SFN on the pistol stretches the brass more than with out it.