.300WM freebore

[RV-Customs]

I'm rebarreling a Rem700 .300WM i have. Currently I shoot 180gr Barnes TSX bullets .040" from touch and would like to stay with them. I have ordered a Krieger #2 Heavy Sporter and will finish it at 26" + muzzle brake. I'm about to order the reamer from JGS and would like some feedback on freebore. This rifle is mostly used within 450yds and I don't use VLD bullets, Any feedback-input would be apprecated. RV

 

[Bart B.]

SAAMI spec chambers have zero freebore and a 1 degree 26.4 minute throat angle.

You can give JGS your bullet dimension specs and what reloaded round COAL you will use and they should be able to make a reamer to fit your ammo spec.

Note that bullet's contact point in throat will advance down the bore about .001" every 15 to 20 shots.

 

[RV-Customs]

Thanks for the info, I just got in touch with JGS and am sending them a dummy round.

 

[Bart B.]

Thanks for the info, I just got in touch with JGS and am sending them a dummy round.

JGS may also want to know if your ammo will headspace on the case belt or shoulder.

 

[FatBoy]

JGS may also want to know if your ammo will headspace on the case belt or shoulder.

I have been using the A191 chamber in mine and having them throated to the bullet/OAL but I am pretty sure I'm going to to order a reamer and co-headspace with a short freebore so we can tweak the throat for the round. I co-headspace now but it required an initial firing to blow the shoulders forward. 020", then I set the shoulders back to .005" HS and it has worked very well. Trying to cut out that first step and having to have two loads. One to fire form the cases and a final load. The 300wm has too little barrel to waste 100-200 shots blowing out cases.

 

[Bart B.]

I co-headspace now but it required an initial firing to blow the shoulders forward. 020", then I set the shoulders back to .005" HS

Would not .005" head clearance to bolt face result in shorter case life than .001" or .002"?

 

[FatBoy]

Would not .005" head clearance to bolt face result in shorter case life than .001" or .002"?

Almost certainly, but it's a field rifle and I like a little insurance. I am getting 6+ firings on Win blue bag brass with a 230gr Berger OTM at 2800fps in a 26" 1:10 Douglas. That's with 74gr Retumbo. Starting to get the tiniest flow into the M700 firing pin hole. According to some I'm not really pushing it that hard, but it's accurate and about as much as my shoulder can take and to me, looks like it's right on the edge of starting to see pressures when it's humid and in the 90s.

I am about to test some ADG brass. If I like it I will probably ask JGS to cut me a reamer for it, for a field rifle.

Never though I would own a belted magnum again but I have to admit I really enjoy shooting the mk13s IF I have the suppressor on. My 700/300 on the left and a "cloned" mk13 mod7 on the right.