M24 Freebore

[RifleMaster]

What is the typical M24 chamber freebore? I would guess at about .020 inch to allow for ammunition variation. Although, I think the typical Remington 700 freebore is about .050 to .070 of an inch.

The free bore can be easily measured with a Mo's or RCBS Precision Mic (about $30). These tools are needed to setup dies to seat bullets close to the rifling. You can't use OAL (over all length) because the bullet nose position relative to ogive vary from lot to lot and big time between manufacturers.

You can use a Match round to setup your die, but you would only obtain standard Match ammo distance from the rifling in your rifle!

What is your experience?

Carl

[medicjim]

I have a bullet comparitor device which allows one to measure a standard distance off of the ogive...the device looks like a giant nut with a hole drilled in each outer surface.. the wholes are sized for many of the standard calibers.

I measure the length of my "throat" with a stoney point gauge (measured 10 times with different bullets of the same lot, take average). I then establish a comparitive measure using the comparitor by simply adding the throat measurement to the length of the comparitor device.

I then load up a case (without primer or powder) and start the bullet with my adjustable redding or forster seater at a very long length and slowly screw down the depth until my "finished" round matches the objective length on the comparitor.

From there, I can set my "jump" where-ever I want it.




[This message has been edited by medicjim (edited 03-08-2001).]

[RifleMaster]

Hi medicjim!

I basically use the same method of establishing bullet seating depth.

I use a Stoney Point Gauge to establish the throat/rifling depth, and then use my RCBS Precision Mic to measure the base to ogive length. Then I seat a bullet long and adjust the seater die down until I have the base to ogive length that I want. I usually adjust to 0.005 to 0.010 of an inch off the rifling.

I also use the RCSB Precision Mic to measure and set dies for desired case shoulder set-back.

Keep Holding'em Hard!

Carl