300 BLK Build Question [Archive] - M4Carbine.net Forums

evotistic

04-01-12, 09:58

So I am contemplating a MK18 semi-clone build, but want to chamber it in 300BLK, hence the semi clone. I would use the DD MK18 RISII rail(9.5") and possibly a Noveske 10" barrel (seems to be the closest to the 10.3" that the MK18 actually has). Is there a combination of FH (ex. AAC 51T) and suppressor that would fit with that barrel and rail combo?

Thanks for any help.

JasonM

04-02-12, 10:07

So I am contemplating a MK18 semi-clone build, but want to chamber it in 300BLK, hence the semi clone. I would use the DD MK18 RISII rail(9.5") and possibly a Noveske 10" barrel (seems to be the closest to the 10.3" that the MK18 actually has). Is there a combination of FH (ex. AAC 51T) and suppressor that would fit with that barrel and rail combo?

Thanks for any help.

With that rail, you'd need at least 1 10.3" bbl if you want to run an AAC Flash Hider and can... and if you want to use an AAC Muzzle Brake or Brakeout Comp with a can, you need at least a 10.5" bbl.

rob_s

04-02-12, 10:26

Good rule of thumb for most of your AAC and Surefire cans is that you need to have 1 between the stated barrel length and stated rail length.

So
10" barrel - 9.0 handguard = 1.0 = OK
10.3" barrel - 9.5 handguard = 0.8 = may NOT be OK
10.5" barrel - 10.0 handguard = 0.5 = NOT OK

You *may* find that the YHM series of cans works for you. They tend to mount the can forward of the crown and therefore a 10.5" barrel with a 10.0 handgaurd *may* work.

evotistic

04-02-12, 17:49

Thanks all. That was exactly the info I was looking for. I am going to look into the YHM cans to see if they will work.

Would it also be acceptable to purchase an 11" or 12" and send it to a company like adco to be cut down and re-threaded at 10.3"?

JasonM

04-02-12, 18:44

Thanks all. That was exactly the info I was looking for. I am going to look into the YHM cans to see if they will work.

Would it also be acceptable to purchase an 11" or 12" and send it to a company like adco to be cut down and re-threaded at 10.3"?

Possibly, but 300 BLK guns can be finicky with gas port sizing if you change the length, so if you send it to someone competent, they can cut it and then adjust the gas port to work.