Higher than expected SD/ES with new brass

[King_beardsly]

I switched over to virgin brass (Starline SRP 308) from the once fired stuff I’ve been using and while doing load development on it I noticed what I consider higher then expected or wanted SD/ES. I got an SD of 11.7 and ES of 33.23 with 43.3 of varget and SD of 24.38 and ES of 86.32 with 45.1 of the same powder pushing 169SMK’s with CCI450’s lighting everything off.

It’s not my first rodeo with reloading but first endeavor in loading 308, I’ve done 6Dasher and 6cheatmoor with good results along with low SD/ES but something either went wrong or I’m expecting to much from virgin brass. I ran it all through my sizing die and used a mandrel to get consistent neck tension, along with chamfering the case mouth to alleviate that being a variables in that regard.

 

[OREGUN]

My experience is that the best es/sd will be with 1x fired brass. Virgin is never quite as good as once fired. Your mileage may vary.

 

[King_beardsly]

My experience is that the best es/sd will be with 1x fired brass. Virgin is never quite as good as once fired. Your mileage may vary.

That’s what I figured but I’ve never actually checked SD/ES with virgin brass, since I used to make “break in” loads with fresh brass for new calibers barrels. I didn’t do load development till I had rounds down the barrel and subsequently I would use the brass from break in for that.

 

[918v]

I dunno if a small primer is strong enough to light that much powder.

 

[King_beardsly]

I dunno if a small primer is strong enough to light that much powder.

You’d thing a magnum primer would have the power to light off that charge weight.

 

[918v]

You’d thing a magnum primer would have the power to light off that charge weight.

A large primer has more priming mix than a small magnum primer. The collective wisdom of the last 60+ years indicates the 308 needs a large primer.

If you had access to other small magnum primers you might find one that might work better with your combo.

 

[OREGUN]

Palma guys have been ”making do” with small primers in .308 for….well…forever. How many rounds are you shooting to get those stats?


ETA: it’s probably worth reading some over at accurateshooter.com. They are honestly much more well equipped to address the SRP Vs LRP discussion when it comes to very accurate .308 than anyone here in sniper land.

 

[King_beardsly]

A large primer has more priming mix than a small magnum primer. The collective wisdom of the last 60+ years indicates the 308 needs a large primer.

If you had access to other small magnum primers you might find one that might work better with your combo.

Currently they are the only small primers I have on hand, I might have to try the equivalent load in the large primer brass I’ve got.

 

[camocorvette]

I've had better SD/es with srp 308 then I've had with lrp. I use cci 450's. Works great

 

[918v]

Palma guys have been ”making do” with small primers in .308 for….well…forever. How many rounds are you shooting to get those stats?


ETA: it’s probably worth reading some over at accurateshooter.com. They are honestly much more well equipped to address the SRP Vs LRP discussion when it comes to very accurate .308 than anyone here in sniper land.

This is an argument of what is possible in an ideal environment vs what works reliably. It’s like when Sacramento County Sheriff bought Toyota Camrys for patrol use. Didn’t work out too good.

 

[ma smith]

Starline ≠ Lapua
SRP≠ LRP in the month of March

 

[OREGUN]

Currently they are the only small primers I have on hand, I might have to try the equivalent load in the large primer brass I’ve got.

The best load may not be the same in LRP VS SRP, FWIW. Probably can’t just try the same load and expect results that are comparable.

As for the rest of yoos:

The OP was asking about virgin brass vs “other” brass as regards ES/SD. I’ll bet a dollar he will see a reduction in both metrics when he tries the same load in once fired brass. Did he mention unreliable ignition? Nope. Did he ask about one being better than the other? Nope.

His use of SRP brass was not a part of the question. CCI450s and Varget are as reliable as anything in .308.

FFS this place is intolerable.

 

[Doom]

The best load may not be the same in LRP VS SRP, FWIW. Probably can’t just try the same load and expect results that are comparable.

As for the rest of yoos:

The OP was asking about virgin brass vs “other” brass as regards ES/SD. I’ll bet a dollar he will see a reduction in both metrics when he tries the same load in once fired brass. Did he mention unreliable ignition? Nope. Did he ask about one being better than the other? Nope.

His use of SRP brass was not a part of the question. CCI450s and Varget are as reliable as anything in .308.

FFS this place is intolerable.

Actually I do not think the OP asked a question.