VASCAR2 Wrote:A couple 6.5 Grendel manufactured bolts/BCG use a shorter firing pin. The reason is because Bill Alexander used .136 bolt face depth. A standard AR-15 5.56/223 bolt face depth is .125” and the bolt length is 2.800”. Bill A. lengthened the 6.5 Grendel bolt to 2.8100” to permit the use of the same length firing pins as AR-15’s in 5.56/223.

When Odin Works released their 6.5 Grendel BCG they used .136” bolt face depth. Odin kept the same bolt length at 2.800”. Odin Works barrels started getting reports of pierced primers which was traced to excessive firing pin protrusion. The spec for firing pin protrusion on an AR-15 is minimum .028” to maximum .036”. It was discovered Brownell’s BCG use the .280” length bolt but use a shorter firing pin. Odin last reported uses a shorter firing pin. Early Toolcraft 6.5 Grendel bolts were reported to be 2.800” length but Toolcraft supposedly switched to 2.8100” length bolts.

The AR-15 spec for AR-15 firing pin length is 3.280” with a tolerance of -.009”. I wouldn’t run a firing pin longer than 3.269” long with a 2.800” length bolt. There could be other 6.5 Grendel bolts manufactured with a length of 2.800”. I would not mix up my firing pins in an AR-15 as you can get into tolerance stacking. You can’t assume any AR-15 firing pin will automatically fit every 6.5 Grendel AR-15. There is normally a tolerance of + or - .002” or more in AR-15 parts.

If I needed to shorten an AR-15 firing pin I would buy a Stainless Steel firing pin over a chrome lined CMV steel firing pin.

VASCAR2 Wrote:Brownell’s has got 6.5 Grendel firing pins in stock and I suspect these are the shorter length to accommodate the 2.800” length 6.5/ Grendel bolt. There was a question as to this firing pin link but I think the length was misprinted. I think the length should be 3.268” and not 3.368” as printed. If 3.268” is correct then that is what is needed with a 2.800” length bolt.

I contacted Brownell’s Technical staff after it was discovered Brownell’s was selling 2.800” length bolts and explained the potential for pierced primers. Brownell’s Tech stated he was not aware of this issue. Later Brownell’s listed a shorter firing pin for sale.


https://www.brownells.com/gun-parts/rifle-parts/rifle-bolt-parts/ar-15-6.5-grendel-firing-pin/

VASCAR2 Wrote:I’m basically summarizing what has been learned and discussed on this form. I measured all my AR-15 bolts and firing pins to verify everything is within spec. All my AR-15’s have been purchased and assembled by me as I haven’t purchased a complete AR-15 rifle.

My intent is to keep shooters from being hurt or having damaged firearms. When you move to other calibers/cartridges in the AR-15 there is less standardization compared to 5.56/223. I just saved all this information in the event this topic comes up on forums.

There is quite a knowledge base of members on this forum and I have learned a lot but I’m just a firearms enthusiast and retired LEO.

Firestarter123 Wrote:Faxon confirmed that they use a 2.800” long bolt as well the other day.

ETA: I’ve spent a lot of time on here the last week learning after buying a couple of 12” barrels from Faxon on a whim the other day when I saw they were on sale. I am just waiting on bolts from Maxim, a couple of magazines, gas blocks, and some ammo in order to try mine out. I need to get dies, brass, and bullets at some point too.

Firestarter123 Wrote:Faxon confirmed that they use a 2.800” long bolt as well the other day.

ETA: I’ve spent a lot of time on here the last week learning after buying a couple of 12” barrels from Faxon on a whim the other day when I saw they were on sale. I am just waiting on bolts from Maxim, a couple of magazines, gas blocks, and some ammo in order to try mine out. I need to get dies, brass, and bullets at some point too.

biodsl Wrote:Welcome to the Forum. I had to laugh. We joke that this cartridge is addictive and they seem to multiply. It's difficult to own just one. You bypassed all that and bought two right off the git-go!

Steve_evetS Wrote:Sweet I wanted to get a Faxon 18" heavy fluted. U should put them thru the fit & finish tests and borescope them before you start laying lead. I ran into some real problems from a manufacturer that has a name simmiliar to the planet that has rings just spelt differently and their customer service SUX.