308 / 6.5CM FP tip sizes, and the variety I found. ( DPMS pattern )

Non-PSA Products AR10 Rifle and Pistol
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This is gonna be about the various FP tip sizes, and styles and bolt FP holes I have found.

IMHO… All manufacturers should post FP tip sizes and bolt FP hole diameters… Yeah I know… Good Luck.

Much like everything else in the Non- Mil-spec world of Large Frame AR’s ( LFAR ) … firing pins and bolt face FP holes can vary by quite a bit.

I am posting so someone can hopefully avoid using / purchasing a incorrect FP size.

This is not a be all list , but is some of the brands I have bought and measured… Please NOTE, the FP style also varies… IE , Tapered v. standard.
Tapered on the left… standard on the right… the middle is in the pic because of the less than squared of edges at the rings.

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I will say , and to cut to the chase… try to buy a brand bolt that comes with a firing pin.

Using a wrong size FP tip size , in a poorly matched bolt FP hole diameter will cause excessive primer cratering and primer flow.

Measurements were done with a Pin gauge set and caliber.

For the “most” part, “standard” 308 BCG’s and bolts ( Non HP ) come with a approximate FP tip size of .076-.079 and bolt FP hole of .080-.083

My List of measured “308” FP tips and Bolt Hole sizes…

PSA / Toolcraft 308 BCG… FP tip size… .077" , bolt FP hole… .081
10ea PSA FP measured… varied between .076" ( 2ea ) .077" ( 7ea )and .079" ( 1ea )
Standard style. ( Non Tapered )

Please NOTE… the PSA dual ejector 6.5CM BCG uses a smaller HP FP tip size . More later

Links provided to be specific.
https://palmettostatearmory.com/psa-pa10-308-nitride-bolt-carrier-group-516446490.html
https://palmettostatearmory.com/psa-pa10-308-nickel-boron-bolt-carrier-group.html
https://palmettostatearmory.com/308-firing-pin.html

Lantac 308 FP , Nib 308 Bolt, and Nitrated 308 bolt, … .076" FP tip size ( 4ea ) .081" Bolt FP hole on both… these are sold as “spare parts”.
Standard style. ( Non Tapered )

PLEASE note… the Lantac ENHANCED BCG ( NOT THE HP ENHANCED ) uses a different FP tip size and Bolt face FP hole !! ( More later )

https://www.lantac-usa.com/product-page/lantac-308-7-62-bolt-choose-finish-nib-qpq
https://www.lantac-usa.com/product-page/lantac-308-7-62-firing-pinFP

RTB Blem 308 BCG ( Toolcraft ? ) … .076" FP tip size,… .080" bolt face FP hole.
Non tapered FP.
Link no longer available

Others measured info…

Fulton Armory actually shows a 308 Bolt for DPMS pattern… for use with a .078" FP
https://www.fulton-armory.com/bolttitanstripped.aspx
https://www.fulton-armory.com/bolttitanstripped-2.aspx
https://www.fulton-armory.com/firingpinchrometitan.aspx

msgriff… “The original DPMS LR-308 bolts were a 0.080” bolt face firing pin orifice with a 0.076" firing pin tip diameter."
Non tapered.

Top O’ Texas tapered v. standard profile FP photo… Some of the tip sizes vary on the Tapered FP and Standard profile.

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PA-10 Firing Pin compatibility
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IMHO, use of the JP enhanced FP in a “DPMS” typical bolt … will induce primer flow / cratering.

Again… buy and use your FP and Bolt from the same manufacturer… and you will be just fine.

While JP is a “standard” default for HP Bolts and FP’s… the also sell a “standard” “Enhanced” 308 bolt and FP.
JP standard Enhanced FP ( 3ea ) .0735" … both the Titanium and standard
I didn’t order the Bolt for these… but given JP’s OCD, Lol… I would imagine a NON HP Bolt face hole of around .077" ish.

https://jprifles.com/buy.php?item=JPEB-308
https://jprifles.com/buy.php?item=JPFP-308
https://jprifles.com/buy.php?item=JPFP-308TI

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Small Diameter / HP setups… Both Tapered and Standard profile FP.

PSA / Toolcraft 6.5CM Dual ejector BCG… FWIW, my first one of these comes from May 2018. And the latest from a month ago.
Tapered SD Tip FP… .068 and .069" , Bolt face FP hole… .071"
https://palmettostatearmory.com/psa-nitride-6-5-creedmoore-bcg-with-double-ejector.html

PSA Single ejector 6.5CM …
Tapered FP, … SD Tip size… .067" … bolt face hole… .070"
Bought years ago … so no link.

CMC / Santan complete 308 BCG ( with 3 exhaust ports on the carrier , “Suppressor Optimized” , single ejector )
Tapered FP SD Tip… .067"… bolt face FP hole… .070"
https://cmctriggers.com/product/cmc-ar15-bolt-carrier-group-suppressor-optimized-milspec-black-nitride-308/

Lantac “Enhanced complete 308 BCG”… single ejector, “forward facing gas ports” w/ Small Diameter FP Tip size and Bolt face hole.
NOTE… the The Lantac sold Bolt and FP I mentioned in the first post… DO NOT interchange parts, with this Bolt and FP tip size … one or the other Bolts and FP’s most be used with the other.
You can use the the other mentioned individual Lantac Bolt Spare parts, and FP , with the carrier. But the FP tip sizes matter.
As in … the Larger tip sized FP won’t work with the “Enhanced” bolt face small diameter hole.
Tapered SD FP tip size… ( 2x ) .067… Bolt face FP hole… .070"
https://www.lantac-usa.com/product-page/enhanced-bcg-full-auto-style-223-5-56-nitrided

Rubber City Armory…
.066" tip size with a regular shank. ( Non Tapered )

https://rubbercityarmory.com/product/firing-pin-for-308-hp/
“Engineered specifically for the High Pressure 308 bolt face.”
https://rubbercityarmory.com/product/308-win-multi-hp-calibers-bolt-firing-pin/

2ea spare tapered SD FP tip sizes… I have little idea where I bought these years ago…
.068" and .069" tip size.

Recently bought Headspaced to barrel bolt and FP to a Craddock Precision RTR 308 Barrel…
Tapered SD FP tip size… .067" , Bolt face FP hole size… .071"

.

Other folks info… along with interesting comments.

“Cascade Hemi” probably Toolcraft… Tapered SD FP tip… .0675", Bolt face tip hole… .069"
Also from Cascade Hemi… Here is the No Name Low Mass bolt/BCG in the picture above:
https://www.righttobear.com/lightweight-ar10-dpms-pattern-bcg-308-bolt-carrier-group-black-nitride/

“NtxGlock” “Noveske sent me a headspaced hp bolt but no firing pin”… "Noveske told me they do not sell individual pins and they sourced that bolt from Rubber City Armory… I have sent Rubber City Armory a email. No reply yet. I did get another dual ejector bolt today w/pin from them (RCA).

Update: Rubber City Armory called me this afternoon. The tech told me that they do NOT sell AR10 bolts to Noveske, only 5.56 bolts. So, I will get back with Noveske. Jeez."

Top O’ Texas… “Also, the design keeps you from using a tapered pin in a non-hp bolt and vice versa. I can’t say that about all hp bolts/fp’s, only the few I have.”
I haven’t checked this out, yet… but…

FWIW… I have yet to see the Tapered SD FP tip size for sale by itself. HOWEVER… I do have 2 spares, Lol
I have some of the Toolcraft AR10 Small Diameter Firing Pin, on back order.

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After receiving the Toolcraft SD FP tip size… I will update the thread.

And as mentioned… hopefully this can help others that want spare parts.

I have also e-mailed Craddock Precision, asking where they source their supplied headspaced bolt and Tapered FP.

For anyone with more measurements… please add your info !!

Thanks ahead of time

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Azimuth / Aero Precision Nitrided 308 / 7.62 BCG Single Ejector

To Aero’s credit they at least publish a comment concerning the size of the firing pin hole. “firing pin hole diameter is reduced to .070”

TAPERED SD FP tip size… .068" … Bolt face hole… .070"

https://www.aeroprecisionusa.com/308-bcg-black-nitride

Tell tale, rounded gas key ends of the Azimuth 308 BCG…

Slab Side of the Azimuth / Aero nitride 308 BCG…

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And I just realized, I never posted the Rubber City Armory ".308 Win+ Multi HP Bolt and firing pin info.

Proprietary SD Non-Tapered FP… .066" , Bolt face hole… .071"

https://rubbercityarmory.com/product/308-win-multi-hp-calibers-bolt-firing-pin/

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Recently bought Headspaced to barrel, bolt and FP to a Craddock Precision RTR 308 Barrel…
Tapered SD FP tip size… .067" , Bolt face FP hole size… .071"

Craddock Precision says… ( via e-mail ) “We get all of our Bolts/BCGS/Firing Pins from Azimuth”

Now… since I have seen the Tapered SD FP in many other BCG’s, I really don’t know if Azimuth makes them.

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I also contacted Aero, asking if they sell the Tapered SD FP as a replacement part.

And while Aero CS was prompt and very helpful… they do not sell it separately.

For that matter… ( and I am sorry to say this ) “one of the techs” recommended buying a replacement from some of the above listed places. NONE of which would have been correct sized or style ( tapered ) . As in to big ( stuck ) and way to small. ( bad primer cratering, if not pierced primers )

It is sad the e-mail contact, while doing his best to help, got piss poor info from “one of the techs”… someone that should know better.

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CMMG Mk3 6.5 / 308 HP BCG…
https://cmmg.com/bolt-carrier-group-mk3-6-5-creedmoor

Bolt face hole … .0635" , SD Non Tapered FP, .059"

I also have some spare FP, and rehab kits on the way

CMMG spare FP’s arrived… . 075", both the individual and the Bolt replacement parts kit. These are not for above mentioned 6.5CM HP BCG
Note… the webpage says “.080” for these specific parts.
( I could not find the HP SD FP , sold on CMMG’s webpage. )
https://cmmg.com/firing-pin-mk3
https://cmmg.com/parts-kit-mk3-bolt-rehab

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Craddock Precision… has come through with replacement Tapered SD FP’s.
These should fit / be suitable replacements for … ( links above in the tapered SD FP section )

Of course, the Craddock Precision BCG and bolt
PSA/ Toolcraft dual ejector SD BCG’s … and older single ejector SD BCG
CMC 308 BCG
Lantac ENHANCED 308 BCG ,… not the “Mil-spec” 308 bolt.
Aero Precision , current phosphated and Nitrided 308 BCG

IMHO, Joshua at Craddock Precision went way, way above any other company.

He will arrange, my buying some from Craddock Precision, ( he also said others can do so as well. ) I will order enough spare of the SD Tapered FP’s for others if they need them.

Aero said no, Never heard back from CMC , Toolcraft never responded… other places have a indefinite back order and they don’t seem to know if the FP is tapered or not. And webpage photos are typically a crap shoot.

I REALLY wish the various webpages would sell proper replacements for their own products. ( Lantac, CMC, AERO, Toolcraft / PSA ) and … at the very least, show the measured FP tip sizes used and style. ( Tapered v. Traditional )

I will post the Craddock Precision, SD tip sizes and pics after I get them… and if someone needs one…IM me.

So… again a huge Thank You to Joshua Bales at Craddock Precision !!

“If you have people who want to buy more you can send them my way, I don’t mind answering emails!” … jbales@craddockprecision.com

Craddock Precision now shows the Tapered SD Tipped FP , they use, on their Webpage.

https://craddockprecision.com/ar10-lr308-hp-308-firing-pin/

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KAK / Azimuth Technology, Double Ejectors… NON Tapered FP , typical Non-SD FP Tip size.
Good fit though ! … Bolt orifice hole… .079" , … FP tip .077

Replacement FP’s sold at KAK… 2ea @ .076", 2ea @ .077"

https://kakindustry.com/lr-308-double-ejector-bolt-carrier-group

https://kakindustry.com/lr-308-bolt-carrier-group-firing-pin

Random internet photo showing the Double Ejector’s…

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The Craddock Precision / Azimuth Tapered FP’s arrived… 11 of the 12 are .0675… 1 was .068

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Nice post.
Very informative and well presented. I now know for sure that there are gun enthusiasts like me, and then there are precision rifle experts like yourself. I am very interested in reading and doing research on precision long range shooting. I do not own any rifles like this, but have been trying to figure out how the AR platforms stack up against bolt action rifles. I have been leaning towards bolt action. I have researched some about the .308 and 6.5 Creedmoore. Most people favor the .308. I have studied ballistics and have seen where while the .308 overall packs more ft pounds, that at 700 yds, the 6.5 CM surpasses the .308 in ft pounds energy.

I appreciate the information and research you have done and provided here. I do realize (to some extent) how significant firing pin and primers were in the ballistics equation. I am no expert, and don’t really have the money to get into the long range target shooting game. But I am sure both hunters and target shooters will be able to up their game from your posts here. Especially when choosing AR platforms and BCGs.

On a different but related note, when I was a B-52 gunner operating the 20mm the firing pin while impacting the primer also delivered up to 300 volts DC through the firing pin. The exact amount of voltage delivered depended on air density and air temperature. I figure, and if I remember correctly, time of flight, target range and closure speed was the reason for this. Of course the ballistics computer figured this and many other factors to achieve prediction angle.

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I guess I forgot to mention that the longer projectile of the 6.5 CM is more stable and less affected by crosswind too, so it has that to consider. I’m not promoting this round over the .308, just felt it was worth mentioning.

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FWIW… I “built” ( really assm’d ) a PA65, with a 22" Criterion barrel, and all the “accuracy enhancing tricks” I could do.
Snugged up the fit between the upper and lower, excellent 2-stage trigger ( SSA-E ), Adj. GB ( SLR) , Trued the upper receiver face, Loctited the barrel in place ( 609 ), Made SURE there was zero chance of contact between the handguard and barrel.

After all that was done… and with ammo it likes, it did this at 100yds.
10rd Hornady Amer. Gunner
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! (2)

The same for a Criterion 18" 308…
IMG_3106_JPG-860403

If I can do it…so can others.

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Wow you did alot of homework, if you will, this is quite the thread. Thanks for all the effort you put in it… as I read through it I keep thinking back in the day…LOL, when I got into the AR-10s it was an ArmaLite AR-10 A4 CB and at that time there “Was a Standard” not milspec but a standard…it was either ArmaLite pattern or DPMS pattern. As time has gone on everyone started making their own308 rifles…One Correction to this. Rock Rivers was also in the mix, they were the first to make their 308s proprietary by changing the thread pattern on the barrel nuts and the receiver height. I was thinking about writing an article for the forum about the AR-10 and 308 ARs…I might have to pick up on it again…
In all your research what NON-psa Firing pin will replace the OME or did I miss something.

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I wanted this separate…Bottom line, IMHO, is PSA needs to get with the program as do others…
IF you are going to sell a rifle in 308 or other calibers then You NEED TO SUPPORT THOSE RIFLES. with parts…Period. I am actually thinking of selling mine just because of that fact… What does it say to the customer who buys the rifle but can’t get parts and is told…contact the company who makes the bcgs and that company says we don’t sell to the public…check these sites…and still you can’t find the parts…Sorry to rant, i’ll get off my soapbox.

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If you can link to your specific PSA BCG, I can probably help.

PSA sells both the SD FP ( Typically the dual ejector )
And a “typical” single ejector BCG, with a more commonly used size.

Maybe even post a pic of the FP ? Tapered or Straight ?

Do you have the means to measure the tip size ?

And FWIW… a lot of places do not stock, or sell a replacement FP… Aero is a good example.
A lot of places also sell FP’s, but they don’t fit all their bolts… Lantac, JP. So that can be confusing.

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Awesome. Like to see what you could do farther out. I know you could do great. Windage and gravity make it a challenge, but the challenge would make it interesting.

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I have taken the 22" 6.5 out to 1500yds , the altitude, and total lack of wind, made it possible to make hits on a man sized steel torso target.
Seriously though… the conditions were perfect. The time was around 10am. So the wind had not picked up yet.

Also the steel torso target was surrounded by loose dirt… so any miss was easily seen.
I did not hit every time… but I did hit the target a few times.
The 300WM that was available , made hits easier.

That same trip I was even making consistent 700yd hits with a 20" Krieger in .223 Wylde, with Hornady 75gr Steel Match.

So to mention again, the ambiant conditions were as close to perfect as I have seen.

I even got one of my friends to make those 700yd hits ( actually 719yds ), he was so inspired, he went out and bought a rifle for his own practice.

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