With a 2.810 long bolt you need a mil spec length firing pin. The 223/5.56 bolt with the designed bolt face depth of .125 +or- .001 are 2.800. When Bill Alexander adopted the .136 bolt face depth he added .01 to the length of the tail of the bolt so his 6.5 Grendel bolts would accept a standard milspec firing pin.
When other manufactures of the 6.5 Grendel barrels started releasing barrels and their own non sourced AA bolts they used a shorter overall length bolt exactly like the 5.56/223. These manufacturers using .136 bolt face and 2.800 length bolt decided to use a shorter firing pin to preclude having pierced primers. It is not difficult to shorten a mil spec firing pin to work with a Brownell, Toolcraft, Odin or Larue bolt. If you try to use your shorter firing pin with your Group Buy Monter bolt you might encounter failure to fire due to insufficient firing pin protrusion.
Just another nuance associated with the 6.5 Grendel. Another confusing thing is the slight differences in length due to allowable tolerances. I dont know the specified length of Milspec AR-15 firing pin.
I measured my Group Buy Monster bolt overall length at 2.812
Im using a PSA Freedom Nitride bolt carrier & firing pin overall length 3.278
I measured my PSA Premium 5.56 bolt overall length 2.800 - 2.780
I measured the firing pin from Premium Bolt 3.278
Here is a thread with a lot of information on the Brownells 6.5 Grendel BCG with pictures and lengths.
http://www.65grendel.com/forum/showthrea...rier/page2
Its possible Larue is sending a full length firing pin with his 2.800 length bolts. I read Larue used a 2.800 bolt but Ive never seen where anyone measured their firing pin. The pierced primers may not occur as frequently with thicker CCI 41 or CCI 450 primers compared to thinner cup CCI 400 or WSR primers when using a full length firing pin.
I never thought to try and measure the firing pin protrusion on my 6.5 Grendel bolt but I previously measured the bolt face depth and it measured .136. My 5.56/223 bolt face was .125 and I didnt think to measure the firing pin protrusion on it either. I dont know the specified protrusion for an AR-15. I could do the math on my bolts but know the exact spec.
When other manufactures of the 6.5 Grendel barrels started releasing barrels and their own non sourced AA bolts they used a shorter overall length bolt exactly like the 5.56/223. These manufacturers using .136 bolt face and 2.800 length bolt decided to use a shorter firing pin to preclude having pierced primers. It is not difficult to shorten a mil spec firing pin to work with a Brownell, Toolcraft, Odin or Larue bolt. If you try to use your shorter firing pin with your Group Buy Monter bolt you might encounter failure to fire due to insufficient firing pin protrusion.
Just another nuance associated with the 6.5 Grendel. Another confusing thing is the slight differences in length due to allowable tolerances. I dont know the specified length of Milspec AR-15 firing pin.
I measured my Group Buy Monster bolt overall length at 2.812
Im using a PSA Freedom Nitride bolt carrier & firing pin overall length 3.278
I measured my PSA Premium 5.56 bolt overall length 2.800 - 2.780
I measured the firing pin from Premium Bolt 3.278
Here is a thread with a lot of information on the Brownells 6.5 Grendel BCG with pictures and lengths.
http://www.65grendel.com/forum/showthrea...rier/page2
Its possible Larue is sending a full length firing pin with his 2.800 length bolts. I read Larue used a 2.800 bolt but Ive never seen where anyone measured their firing pin. The pierced primers may not occur as frequently with thicker CCI 41 or CCI 450 primers compared to thinner cup CCI 400 or WSR primers when using a full length firing pin.
I never thought to try and measure the firing pin protrusion on my 6.5 Grendel bolt but I previously measured the bolt face depth and it measured .136. My 5.56/223 bolt face was .125 and I didnt think to measure the firing pin protrusion on it either. I dont know the specified protrusion for an AR-15. I could do the math on my bolts but know the exact spec.