survivalshop

You will normally see wear marks on the Bolt , but being squared to the rest of the lug is abnormal , like the Bolt was out of battery when cartridge fired off , as you said . I say bad Bolt Metallurgy & may be why it cracked , it happens , but shouldn't . May be a sign of out of spec's component, like Head space or you could have got some really HOT ammo . M16/15 bolts have cracked in the same place , something may be amiss . The Bolt in my photo , which I will look at more closely , was still functioning & caused no problems , but maybe would not have stayed that way . I'm using the same Barrel it was in with the SOW NIB BCG & no problems.

I'm all for t-shirts , as long as they are not Black , before you cockroaches say some thing , the color is too hot down here to wear . FDE ? <thumbsup>

Good Job !

Thats the Bit size , Damn , I thought I read the conversion some where in this thread . I just used the decimal in my notes instead of the fraction . You are sooooooo smart Robo <thumbsup>

If I can find the thread where we got into a bunch of gas port sizes , we would have some references , but no idea whats its under . My notes read my port on my 16" is 0.1095 " , but I'm not sure if that is right or not . I used a drill bit & don't or can't find that note on it , will keep looking .

I like that , good job !

If you had a chamber problem & enough for the Barrel maker of Gunsmith to say it shouldn't have been shipped that way , I wouldn't be too quick to blame the Bolt . I'm certainly not sticking up for SOW , just pointing out it will be hard to put a definite finger on the cause . What if the replacement bolt shows the same problem ? Carbine gas system on a 308 will punish the action parts , if not regulated & substituting a heavy Buffer may help in one way & can exasperate an over gassed issue. Meaning , longer lock time & increased pressure on the Bolt . There is a fine line to run with respect to individual components & the effects they have on the action , there has to be a balance of sorts , going to a Mid gas system will help . If you look at your second photo , at the back of the Bolts locking lugs , there is a step or drop off , that is a sign of something not right . Be it a soft bolt or another issue with head space , which could be several issues with the chamber , Barrel extension or the Bolt its self . Here are some photo's of three of my 308 Bolts. All head spaced correctly. This is my Fulton Armory BCG ( could be a DPMS ? ) this is from my 20" & has a lot of rounds through it , no idea how many , but a lot . This is my SOW BCG from my 16", & has less than 1K through it . This BCG was in my 16" before I installed this same 16 "Criterion BBL. in a different ,Tactical Machining Upper Receiver & DPMS Lower Receiver last year . It is showing the same step at the back of the Bolt locking lugs , which I think is a soft bolt with poor hardening procedure . This bolt has over 1K rounds through it & had no problems , except the rifle would not reliably function with Magpul PMags . This Barrel ( 16" )was originally in a SI Defense Gen.II Billet Upper Receive & a very early CMMG Billet Lower Receiver . Good luck on getting anything replaced right now , but keep at it , you might be successful with time . I would just get a new Bolt & be done with it

Is that a M16 Carrier or enhanced AR 15 ? I can't tell by the photo's on their web sight & it appears it doesn't say .

Why ?

That's some perty stuff right there !

Here's some of my Chrono testing with Nosler 175 gr. , I have photo's of the targets also . 16" BBL. 175 gr. Nosler Match bullets. COL 2.796 " # 1 - 39.5 gr. IMR 4895 ( on Noslers load data , the most accurate ) ( Annealed FC brass & crimped with Lee Factory crimp die ) Avg. Vel.- 2269 fps ES- 22fps SD- 8 fps # 2- 38.5 WC 846 Avg. Vel.- 2214 fps ES- 53 fps SD - 19 fps # 3- 42 gr. IMR 4064 ( newer CCI primers ) Avg. Vel.- 2466 fps ES - 26 fps SD - 11 fps # 4 - 40 gr. WC 846 Avg. Vel. - 2327 fps ES - 32 fps SD - 12 fps 20 " BBL. 175 gr. Nosler Match bullets , COL 2.796 " # 1- 39.5 gr. IMR 4895 ( again this loading in the Nosler data was there most accurate )( Annealed FC case , Lee Factory crimp die ) ( only four shots in group, all I had left to use ) Avg. Vel. -2392 fps. ES - 69 fps SD - 28 fps # 2 - 40 gr. WC 846 ( there are five shots in that group ) Avg. Vel. - 2446 fps ES - 43 fps SD - 16 fps # 3 - 42 gr. IMR 4064 ( newer CCI Primers ) Avg. Vel. - 2573 fps ES - 17 fps SD - 7 fps # 4 - 40 gr. IMR 4895 ( WW brass , annealed & crimped with a Lee factory crimp die ) Avg. Vel. - 2353 fps ES - 44 fps SD - 15 fps.

Nice !

Any photo's of the brass ? Brass Base , with head stamp ? Try some 168 gr. ammo or 175 gr. just for $hits & Giggles , rifle may just need to break in .

I sent you an order today , snail mail .

Look at the Federal Lake City M855 green tip at the bottom of the page $ 0.84 a round . <dontknow>

And I thought putting a lit Cigarette between arms & see who would more first , was Macho <lmao> & yes we used to do that , I have the scares to prof it , dumb to be young <dontknow>

Lets see if the price comes down <dontknow> <laughs>

I have a DPMS Bolt spare parts kit & it came with : Firing Pin , Extractor & spring , Ejector & spring , & Gas rings I'll take a photo later . Good kit to have in you Pistol Grip or Stock or just having around . I also like to have a complete spare Bolt around for the 308 , but I want NIB & you can get them , but only as a complete BCG .

<munch>

<laughs>

How does the fired brass look ? Any Scratches on the side of the brass , Extractor marks ? Inspect the chamber for roughness . Polish if necessary , one would think your Barrel guy would have checked all that , but you never know unless he said so .

I have to look up what drill bit size my 16" is . Its in a thread on this forum , some where & I have it written some where in my notes , but it may take me a bit to find it .

Ya, its tapered or something , there is a thread on it some where here . Unless that part of the barrel was untouched . I think the 24 " Barrel will have a smaller gas port than a 16" , there's a lot of Barrel after the port on a 24 ". although, was it opened up enough , that's a good question . You may also check some basic things also , enough Lubricant on new build ? DPMS Chambers were notorious for having rough or tight chambers also. Head space been checked ? As has been asked what stock system & its components , all 308AR ? Could also be bolt bounce , maybe the port is too large ? Does the BCG, hold open on last round ? Try it with one round in the mag & progress to three & see if it holds the Bolt back each test . Have you tried different manufacturers Magazines ?

How did the brass look with 44 gr. ?

Was my first thought , when I read the topic . <laughs>