Need to double check head space. M305

Towlie

Towlie

Member
EE Expired
Rating - 100%
4   0   0
Location
Fraser Valley, BC
I changed out my original bolt for another chinese bolt, I'm just wanting to check the head space to ensure that its safe to fire.

The bolt closes niceley and has some slop wihout ammo being loaded.

If there is someone in the lower mainland (BC) that has headspace gauges I could borrow, buy, or I could pay to check for me please let me know.

Cheers

Zac
 
You'll need the whole set if you buy 'em. At around $34US via Brownell's. $32.20US direct from Forster(or Clymer). Or you can rent 'em from several places Stateside. No border issues for tools. One of 'em is here. Add the W's.
.reamerrentals.com/ProductDetails.asp?ProductCode=308Win%2Eg
Why'd you change the bolt? Just curious.
 
Is your bolt stripped?
A quick n dirty way to just see if you're safe is to use either a loaded round or a case thats been sized to min, this is your "go gauge".
Then use calipers and measure the thickness of some tape (electrical is good) and trim a few pieces to the diameter of the case rim and add the pieces until the bolt doesn't close, add the thickness to the number of pieces used and that's your go plus X amount.

It's not perfect but it's within a thou or 2, and in these battle rifle chambers it's enough to tell if it's safe or not.
 
I for some reason around the 800 round mark i cuoldnt keep and extrator in my original bolt for more than 5 rounds. I tried chinese extractors, USGI extrators, and NOS USGI extractors. I also double checked if the extractors were sticking out of the bottom of the bolt and if the were i filled them to fit, but still the would not stay in. I found a really good deal locally on a DA socom 18 bolt so i thought i would try that. I didnt really want to buy go-no go gaugaes but its looking like I will have too which isnt really a bad thing.
 
You've probably already done this, but just a reminder to make sure you check for good lug engagement on both sides with the new bolt.
 
Pop said:
You've probably already done this, but just a reminder to make sure you check for good lug engagement on both sides with the new bolt.
Click to expand...

The new bolt closes nicely and look to have full lug contact, it also isnt tight against the chamber without a round loaded. It seem it might be a bit looser than it should.
Well only one way to find out, it looks like im buying some head space gauges. (GO, NO GO, AND A FIELD IS I CAN FIND ONE)
Any good cheap gause any could recommend?
 
Fire a round in it and have someone measure the case. This will give you a fairly accurate measurement.

Do you handload? If so, seat a primer only part way into a case, and close the bolt and then smack the handle. Then look to see how much the primer is protruding. That is the excess headspace.
 
You must log in or register to reply here.
Back
Top Bottom