Leade on my new DPMS-barreled PA10 (7.62 × 51 AR)

[FOGeologist]

I've been loading my "standard load" for my 6mm Rem K98k, so I had the Hornady OAL bullet comparator out, along with the tool and the prepared shell - it you're not familiar, it allows you to slide a bullet into or out of the case while the shell and bullet are chambered. You can lock in the length at which a bullet's ogive jams into the lands, then set the bullet back 5, 10, 15 (or whatever) thousandths from "jam."

I had just cleaned the new PA10 I built, so I thought, "Hmm, I have a prepared case from the old Rem 700 SPS project laying about, maybe I'll just see what the leade (or is it 'free-bore'?) looks like."

I can only load to 2.808" before the rounds can't be loaded into the mag. OAL to jam is 80/1000!" Do all AR barrel makers allow that much "jump?" it seems excessive. I have some 168 grainers that are fairly VLD (Barnes TTSX), and I'd guess they'll have an even larger "jump."

If you know of any barrel makers that don't allow such a huge freebore, sound off here.

 

[Laphroaig]

OAL to jam is 80/1000!"

Is this a typo?

In the past I was disappointed in the freebore in a .223 barrel DPMS sold to me. It was more like 5.56 dimensions. They did take it back, and I replaced it with a .223 chambered Kreiger. That barrel had a very short freebore in that mag length .223 was 0.020" off the lands.

I know it isn't apples to apples but that's my DPMS story.

Laphroaig

 

[243winxb]

http://www.saami.org/pubresources/cc_drawings/Rifle/308%20Winchester.pdf Looks like SAAMI has a leade/freebore of .090" for the 308 win. The military chamber, may be different, i think?

 

[243winxb]

Looks like NATO leade might be .105" ?? http://www.rangingthoughts.org/gBlog/image.axd?picture=2011%2F9%2F7.62+NATO+va+.308+Win+05small.jpg

 

[FOGeologist]

Thanks for the perspective!

243, thanks for the perspective on the SAMMI vs. NATO standard. The rifle's barrel is clearly NOT intended for hard-core target shooting.

I am unsure how accurate it can be loaded for - I do not have optics yet; only a red dot. We shall see if the jump causes a challenge.