AAC/SD .308-HSM 185gr Berger VLD Case Extraction Problem

[Infidel45]

I have 362 rounds through my rifle and have run the following factory ammo through it thus far with no problems;

147 gr NATO FMJ mil-surplus (100-600 yds)
155 gr Hornady Steel Match OTM (100-600 yds)
165 gr BHA Match SP(100-600 yds)
168 gr FGMM and Remington Match (100-600 yds)
175 gr FGMM (100-1040 yds)

I have fired 8 rounds of the HSM 185 gr Berger VLD and each time the bolt stuck closed after the round fired. I had to stand the rifle on its butt and hit the bolt with my hand pretty hard to get it open. The shell ejected normally once opened. Each time this has happened is has occurred during a range session after other types of rounds have been fired with no issues. No issues with other ammo following extraction.

Anyone have any ideas/Experience as to why this happens? Thanks...

 

[FCS]

Picture of case head would be helpful. Any ejector swipe? How flat are primers?

Several possible reasons but in a nutshell, you are getting higher pressure with the 185 ammo then with other types.

 

[rjacobs]

sticky bolt on a bolt gun is a high pressure issue.

My other advice with the VLD bergers in the AAC/SD is to skip them as they dont jump well. The VLD's were designed to be jammed and are not jump tolerant. The rest of the Berger line is VERY jump tolerant and was designed that way. Juggernaut, LRBT, etc... will all jump well. The AAC/SD has such a long throat you have to seat bullets out to somewhere in the 2.9xx range to get into the lands and this means single feed.

 

[Infidel45]

sticky bolt on a bolt gun is a high pressure issue.

My other advice with the VLD bergers in the AAC/SD is to skip them as they dont jump well. The VLD's were designed to be jammed and are not jump tolerant. The rest of the Berger line is VERY jump tolerant and was designed that way. Juggernaut, LRBT, etc... will all jump well. The AAC/SD has such a long throat you have to seat bullets out to somewhere in the 2.9xx range to get into the lands and this means single feed.

Thanks. Casing is unmarked w/good primer strike in center. It was single fed which i always due during range sessions. I already decided not to shoot anymore of them but i wanted to know if it was going to be a problem with all 185 gr full power ammo...i have some Lapua 185 bthp's i want to try.

 

[rjacobs]

Thanks. Casing is unmarked w/good primer strike in center. It was single fed which i always due during range sessions. I already decided not to shoot anymore of them but i wanted to know if it was going to be a problem with all 185 gr full power ammo...i have some Lapua 185 bthp's i want to try.

I have shot a few hundred Berger 185g Juggernauts/LRBT(same bullet, different name) through my AAC SD with no sticky bolt, but I hand load. Its not the bullet, its that load from HSM. I wouldnt shoot anymore of them in your gun as your gun doesnt like them. Maybe no .308 would like that particular load, I dont know.

If you hand load and want to keep running the Bergers(they are nice bullets, shot well, but to pricey and didnt perform that much better than the 175g SMK's or Nosler 175g CC's to justify the price) try something like R17 powder. Its a touch slower than Varget, easy as hell to find, and seems to run really well with the bullets above 175g. I find Varget about maxed out at the 175's. Im getting ready to do load development with R17 and 175's to see if I can work a load up, but it might be to slow a powder.