09-20-2018, 02:29 PM
VASCAR2 Wrote:SDW, I haven’t seen any post regarding the bolt used by PSA other than they are 6.5 Grendel with .136 bolt face. Bll Alexander chose to use the .136 bolt face to permit more room for the extractor. A typical 5.56/223 bolt has a .125 bolt face depth and the bolt length from face to tail is 2.80. Bill A lengthened the 6.5 Grendel bolt to 2.810 to make up for the .01 deeper bolt. By going to a 2.810 bolt length the 6.5 Grendel can use the same length firing pin as the 5.56/223 bolt (mil spec BCG).
If someone has a PSA 6.5 Grendel BCG which came with their upper measure the length of the bolt. Hopefully PSA did their home work and are using a 2.810 length bolt. Over the years there were a couple of examples of tolerence stacking where a bolt and firing pin had light firing pin hits. There were also a couple of situations with pierced primers because of out of spec firing pins and or bolts. These were very rare situations but when Odin released their 6.5 Grendel it was discovered they were using 2.800 length bolt with milspec firing pins. These 2.80 length bolts with milspec length firing pins resulted in excessive firing pin protrusion and pierced primers.
It is unknown if Odin Works manufactures their own 6.5 Grendel bolts or purchased bolts from another manufacturer. Brownell’s released their 6.5 Grendel BCG at about the same time as Toolcraft and both use 2.80 length bolts. If I were to purchase or use a Brownell’s, Toolcraft or Odin 6.5 Grendel bolt I’d measure the bolt and firing pin. Without measuring the firing pin and bolt length you won’t know what you have because milspec length firing pins have been shipped with the 2.80 bolts.
When LaRue 6.5 Grendel was released one forum member measured his bolt at 2.80 but later another member measured a Larue bolt from an UU kit and the bolt was 2.810. Many times manufactures will make product changes without announcing the change. To be on the safe side I’ve measured all my 6.5 Grendel bolts, firing pins and bolt face depths and all mine were within spec.
I was having primer piercings with the factory firing pin in ny radical upper. I changed it out with the firing pit from a Odin works 6.5 grendel BCG and it went away.
How do you measure the bolt to see what length I have?