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Discussion Starter #1
Will a booster hole size of .8125 work ok for 8mm or is it too large and run slowly ???
 

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booster hole in a m-6 hider is .721 i have seen alot of gi boosters lately and they are marked 7/8 which is .875,but i have not put a caliper to a g.i. one yet to see what it actually is. you should be ok,unless you have a crank fire and you can tell the diff with different booster holes when using a crankfire..
 

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PhD in Over-Engineering
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Speaking of which, who out there is using a 16" shorty in .308, and what booster size are you using?
 

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I am still working on getting my .308 shorty working. No booster (barrel bushing only) didn't give enough impulse and a regular .308 gave too much.

I have heard from a 5/8" to 1" oriface works best.
 

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Lucky#13 said:
Speaking of which, who out there is using a 16" shorty in .308, and what booster size are you using?
I shot up about 2400 rounds of .308 on a 16" bbl using a USGI booster, as well as the M-6 hider. Had no problems at all firing in semi. I can't speak for the crank devices.
 

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Lucky#13 said:
Speaking of which, who out there is using a 16" shorty in .308, and what booster size are you using?

With the smaller barrel Im using a larger hole in my booster
Im thinging a 308 booster on a shorty barrel will make the bolt hit the back too hard

All you need to do is try the larger hole first if it works then it works
you will not hurt the gun with a larger hole. If it doesnt work it will only make the bolt go half of the way back or so

Good Luck:cool:
 

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PhD in Over-Engineering
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Thanks, gentlemen. I have about 1,000 rnds through one with a 308 booster and it functions great, but it occurred to me recently that this might beat the thing up more than needed. I'm going to experiment next time out, perhaps starting with the .718. I have a second that I am about to finish so it's time to sort this out.
 

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Isn't a real 8mm booster suppose to have a .6875 hole? I have a 30-06 on my 8mm and I can pull the trigger faster than the gun can handle. I'm thinking of boring out a .308 booster but I'm not sure what size to make it.
 

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Discussion Starter #9
Yes .6875 is the actual calculated size for 8mm to allow pressures to escape and also cycle the gun properly but you can go a little larger. I am currently running .7344 which is damn close to 3/4". Mine also runs a little slower then what I can cycle it. I can pull the trigger about 2 to 3 more times then what the gun will catch up to so I am going to probably try to down size a little and see if it helps?!?!?!!?:confused:
 

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I just like the way it runs with .308 ammo and a .308 boost, it is nice and crisp. I would like to get the 8mm to run that way also.
 
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