Factory S&B ammo - pressure signs

[Dave_424]

Went to the range today for some general practice and it seems like the S&B 140 and 131 grain ammo is running quite hot. Flattened primers and smeared ejector marks. Only shot a couple of the 131 grain but the bolt lift required slightly more effort than normal.

Based on the pictures below, what are your thoughts. First picture is 140 grain, second is 131 grain and the third is some 140 grain Remington core lokt.

Gun is a Bergara B14 HMR

 

[Smellydog]

Getting there that is. If that was my reloads I'd be backing off a touch..
Typical for s&B ammo though. I don't know why but they seem to do this ...

 

[ashray]

i saw the problem straight away, its a 6.5 crapmoor." long live the true 6.5 the 6.5x55. JOKING ASIDE i would say oil in the chamber causing this issue.

 

[Smellydog]

i saw the problem straight away, its a 6.5 crapmoor." long live the true 6.5 the 6.5x55. JOKING ASIDE i would say oil in the chamber causing this issue.

Hmm usually a flat flat primer is due to the case held in the chamber by peak pressure, the primer banks out of the case and bloats. Then as pressure drops the case releases from the chamber and then is driven over the primer leaving a much flatter and wider looking primer. Oil I don't see how that would cause the op's experience??

 

[Foxyboy43]

Hmmm.
I have noticed S&B can also be a bit snappy in their .308s.
Defo flattened primers and light smiley faces left by extractor so as per Smelly if they were my home loads I would reduce the charge. That said no bolt swipe and from what you said no major effort to lift the bolt so I would continue to shoot them. Be interested to see side-on view of an extracted primer?

 

[trickie]

I’ve shot a few hundred S@B through my 6.5 CM. Both factory and reloaded. The primer pockets are tight and Federal primers and to difficult to seat without flattening them or swaging the pocket. Other than that, the shoot vell in a Tikka Tac A1, Lithgow Woomerer and a couple of other rifles.

what @Smellydog said

 

[nun_hunter]

How hot was it where you are today?

When I developed a load for my Creedmoor in the depths of winter (down south so still 4⁰C)but used these rounds last year when it was topping 31⁰ I was getting similar marks to you.

 

[Dave_424]

Thanks for the replies everyone, seems like I'm not alone with this S&B ammo.

I was shooting in Monmouth in a tunnel range so cooler than ambient. 16-18 degrees at a guess.

Accuracy is actually fantastic so far, and the soft points will do nicely for hunting. So I think I'll stick with them for now. Next is to find some high BC ammo it shoots accurately for long range stuff.

Has anyone tried the Sako range ammo? Box of 50 is round £65. Or am I better off going straight to something that's loaded with a Hornady ELD bullet?

 

[nun_hunter]

The Sako Racehead 140 FMJ in my 6.5 Creedmoor was very accurate and the price I paid it wasn't really worth bothering to reload as it was that good.

 

[Kiwiguy]

If that was my rifle I would be trying to find a cause for the ejector marks. Even two of the Remington cases are showing ejector stamps, the first is over the CRE and the last case is over the R of R-P.

 

[trickie]

Sako 136 is highly recommende, no availability local to me currently though.

 

[malmick]

If that was my rifle I would be trying to find a cause for the ejector marks. Even two of the Remington cases are showing ejector stamps, the first is over the CRE and the last case is over the R of R-P.

Middle one has it too over the DM.

@Dave_424 I've had very good results from ELDm 140gr and 147gr and ELDx 143gr reloads. First factory box I tried were ELDm 147gr, four 5-shot groups all well under 1moa.

I've also found the S&Bs to be hot loads in a 24" B14.

 

[trickie]

Lots of our shooters use the 140 ELDM with great results, sub moa at 600+ with the better shooters/reloaders.
Vhitavouri N555 push them very well, but that difficult to obtain at the moment. The bullets are readily available if you know where. Dauntsey Guns have a decent stock (last night anyway).

trickie

 

[Kyte]

I get the same flattened primers from 140gr s&b sp, I was also getting flattened primers early in load development with n555 and eld x 143’s , couldn’t understand it , turned out I was bumping case shoulders back too far , once I’d resized brass with .002 thou shoulder bump reloaded and fired all primers then looked rounded and totally fine , I’ll measure headspace on a live s&b cartridge and compare with a fired one … will be interesting to see

 

[Dave_424]

I get the same flattened primers from 140gr s&b sp, I was also getting flattened primers early in load development with n555 and eld x 143’s , couldn’t understand it , turned out I was bumping case shoulders back too far , once I’d resized brass with .002 thou shoulder bump reloaded and fired all primers then looked rounded and totally fine , I’ll measure headspace on a live s&b cartridge and compare with a fired one … will be interesting to see

That's interesting and useful to know. I did think that it might be the case that the factory ammo has the shoulder set back more than 'normal' which is causing it to stretch/move backwards excessively. I'd be interested to hear what you find.

 

[A Guy Out West]

Looks like some brass shaving on the S&B stuff. Brass flowed into the ejector hole and was shaved off upon extraction.

 

[Kyte]

I get the same flattened primers from 140gr s&b sp, I was also getting flattened primers early in load development with n555 and eld x 143’s , couldn’t understand it , turned out I was bumping case shoulders back too far , once I’d resized brass with .002 thou shoulder bump reloaded and fired all primers then looked rounded and totally fine , I’ll measure headspace on a live s&b cartridge and compare with a fired one … will be interesting to see

So had a measure and headspace difference between live round and fired brass was .004 thou … so not to excessive.. will stick a few over the chrony next , maybe they are abit hot ???