rdsii64 Posted October 17, 2018 Report Share Posted October 17, 2018 I just took delivery of my new Criterion hybrid profile 20 inch 308 barrel. When I ordered it I forgot to order a corresponding bolt verified to headspace correctly. Now I have to order the bolt and headspace gauges. Whose bolt would you recommend? Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted October 17, 2018 Report Share Posted October 17, 2018 To be honest… This is a question best suited for Criterion barrels. I’m almost positive that Criterion barrels uses Fulton armory bolts. Quote Link to comment Share on other sites More sharing options...
rdsii64 Posted October 18, 2018 Author Report Share Posted October 18, 2018 On 10/17/2018 at 2:07 PM, Robocop1051 said: To be honest… This is a question best suited for Criterion barrels. I’m almost positive that Criterion barrels uses Fulton armory bolts. Yep they use Fulton armory, and JP bolts. I posted this same question on another forum and the Criterion Rep chimed in. They also said DMPS bolts will work too. Thanks for the reply though. Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted October 18, 2018 Report Share Posted October 18, 2018 The 308 world is not as bad as it used to be. I would feel comfortable using almost any reputable “LR-308” compatible bolt. We used to have a hook up, with one of our members. Somebody around here have to remember his name. Several of the longtime members here have successfully used his bolts, in numerous builds. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted October 18, 2018 Report Share Posted October 18, 2018 35 minutes ago, Robocop1051 said: We used to have a hook up, with one of our members. Somebody around here have to remember his name. D. Wilson, he still does a few gunsmith services but doesn't sell BCG's to the public anymore. Check out his sale in honor of being banned on FB; https://www.dwilsonmfg.com/store/c1/store 2 hours ago, rdsii64 said: Yep they use Fulton Armory, and JP bolts. The Fulton BCG I worked with was very nice, bolt is a dead ringer for the JP high pressure bolt. It headspaced on the Criterion barrel nice and snug. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted October 19, 2018 Report Share Posted October 19, 2018 I have used DPMS , Fulton & D. Wilson Bolts in Criterion 308 Barrels , the only one I had an issue with was D.Wilsons & all it took was to change the Extractor to a DPMS one & the Bolt worked fine & all Head Spaced fine . Quote Link to comment Share on other sites More sharing options...
JKN Posted October 21, 2018 Report Share Posted October 21, 2018 I just went through this very process. I ordered a Brownells BCG with the barrel and it was no where close to being able to lock on a GO gauge. They sent me two more BCGs. Exactly same issue. They guessed it must be a bad barrel so they sent me another. Same result. I then ordered a Toolcraft BCG. It was similar in measurement to the Brownells parts and also wouldn't lock. In the end I sent the barrel to Criterion and they matched a Fulton Armory bolt to it for the cost of the bolt and shipping. Great people to deal with. Good luck and let us know what works. John Quote Link to comment Share on other sites More sharing options...
survivalshop Posted October 21, 2018 Report Share Posted October 21, 2018 8 hours ago, JKN said: I just went through this very process. I ordered a Brownells BCG with the barrel and it was no where close to being able to lock on a GO gauge. They sent me two more BCGs. Exactly same issue. They guessed it must be a bad barrel so they sent me another. Same result. I then ordered a Toolcraft BCG. It was similar in measurement to the Brownells parts and also wouldn't lock. In the end I sent the barrel to Criterion and they matched a Fulton Armory bolt to it for the cost of the bolt and shipping. Great people to deal with. Good luck and let us know what works. John Were the Bolts NIB Coated ? Quote Link to comment Share on other sites More sharing options...
JKN Posted October 21, 2018 Report Share Posted October 21, 2018 Not NiB coated just plain Nitride. https://www.brownells.com/rifle-parts/bolt-parts/bolt-carrier-parts/bolt-carriers/308ar-bolt-carrier-group-308-win-nitride-mp-sku078102004-105380-202840.aspx?sku=078102004 https://www.acmemachine.com/collections/bolt-carrier-groups/products/toolcraft-ar-308-bcg-nitride-bolt-carrier-group-armalite?variant=12352308674645 Quote Link to comment Share on other sites More sharing options...
survivalshop Posted October 23, 2018 Report Share Posted October 23, 2018 (edited) Interesting , I have seen NIB coated Bolts with too thick of NIB coating , not pass HS testing & be a little tight on a "GO " gage , but do after a break in round count . I always test the Bolt alone in the Barrel with out any Ejector or Extractor in it & with the Barrel not mounted in a Receiver , then with the Barrel mounted in a Receiver & with the complete BCG without the Extractor & Ejector . Edited October 23, 2018 by survivalshop Quote Link to comment Share on other sites More sharing options...
survivalshop Posted October 23, 2018 Report Share Posted October 23, 2018 There is also another reason that the Bolts would not Head Space , it depends on if you are using the same Gage manufacturer that the Barrel maker is using & I know for a fact that Criterion has a custom Chamber & your Gage set may not give the results you would expect . Quote Link to comment Share on other sites More sharing options...
JKN Posted October 23, 2018 Report Share Posted October 23, 2018 I may be able to find the dimensions around here somewhere but the differences in the breech face and lug dimensions between the final bolt and the ones that wouldn't gauge were substantial. The bolts were all stripped when being checked. As a last ditch effort I tried a sized case that easily fit in the case gauge and while it started to turn it bound up very tight. When I got the FA bolt it gauged perfectly with the gauges I had so there was a big difference in dimensions between the two. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted October 23, 2018 Report Share Posted October 23, 2018 Thats the trouble with 308AR's & those who manufacturer components& parts for them , some make up their own spec's or don't have very good QC . Makes you wonder if the Bolts were tested in a Chamber & if they were who's Barrel or test fixture . Leave a review in the Brownells sight for that BCG , they are pretty good at weeding out or discontinuing problematic parts if they get a lot of bad reviews . They don't make the parts , but do contract them to be made for them . Their 308 Steel Mags with the crap coating come to mind. Quote Link to comment Share on other sites More sharing options...
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