Going from .308 to 6.5 Creedmoor- Do I need a HP bolt too?

PDXGS

Sergeant
Full Member
Minuteman
May 31, 2009
947
844
Northwest Oregon
Hi all, I'm an experienced long-range bolt gun shooter in the process of converting a .308 AR10 to a 6.5 Creedmoor. Assuming that the bolt is a good match/fit, is it necessary to also swap it for a JP high pressure bolt?
I await the wisdom of the forum....
 

knuckleballz

Elk Hunter
Full Member
Minuteman
Dec 12, 2013
533
354
What bolt and barrel do you have now in your 308? What barrel are you switching to?
 
Last edited:

PDXGS

Sergeant
Full Member
Minuteman
May 31, 2009
947
844
Northwest Oregon
Currently running a DPMS "precision" stainless barrel with an Aero BCG and switching to an Aero stainless barrel.
 

Red_SC

Redheaded Stepchild
Full Member
Minuteman
Nov 26, 2003
1,967
88
Florence, SC
The Aero BCG is HP. A standard firing pin hole is .080, the Aero is .070. Some companies make them down to .062, I don't know the JP size offhand.

I use JP bolts in my builds for non-.308 applications, but since you already have it I'd try the Aero to see if there's a problem before replacing it. I do use Aero bolts sometimes in .308 builds including my own .308, they're well made.
 
Last edited:

SFree

Sergeant
Full Member
Minuteman
Jan 20, 2005
780
108
USA
Doing same conversion, but with an Armalite rifle, so possibly no need for the JP hp bolt? I believe the AR-10 bolt firing pin hole is .062...
 

padom

SuperMod
Staff member
Moderator
Supporter
Full Member
Minuteman
  • Mar 13, 2013
    10,397
    5,256
    Southeastern, Pennsylvania
    The smaller firing pin hole is not the only design change of JP's HP bolt. There's a reason JP's HP bolt is the go to standard for people building 6mm/6.5mm semis and is the reason many factory barrel makers headspace to JP bolts like Rainier. Check out JP's site if you want the list of things you get with their HP bolt. RCA HP bolt is the only other bolt I would use in a 6.5cm semi.
     

    SFree

    Sergeant
    Full Member
    Minuteman
    Jan 20, 2005
    780
    108
    USA
    JP doesn't make anything for Armalite/RockRiver pattern rifles,so the bcg/bolt needs to be changed to DPMS type?
     

    SFree

    Sergeant
    Full Member
    Minuteman
    Jan 20, 2005
    780
    108
    USA
    Don’t understand the necessity for a different bolt when chamber pressures should be close and other operating pressures could be controlled by adjustable gas blocks or gas keys. Seems some problems in other systems were solved by switching to an Armalite bolt. Why has the AMU used Armalite almost exclusively if advantages were with other systems besides the magazine issue. This is from searching and reading from the internet so it MUST be true
    My apologies if I’m dense, I’m here to learn.
     

    bfoosh006

    Sergeant
    Full Member
    Minuteman
  • Jun 13, 2007
    1,227
    485
    PNW
    IMHO, it is just as important to make sure the bolt remains locked long enough... IE, make sure to run an adjustable GB and heavy buffer weight and recoil spring.

    Any pressure signs I saw went away , promptly, after allowing the bolt to remain locked just milliseconds longer.

    I also believe... Armalite BCG's have a slightly different cam pin path that aids in a millisecond longer locked action... ( and the gas tube is different )

    Ejector smear marks went away... the whole 9 yds.


    I am not negating the value of the JP bolt at all.... just saying that there more factors to help mitigate pressure issues then just the bolt