OzFclass

Gents,

What anyone using for the freebore amount for there 7mm? Im going to build a 7mm-08AI for F-Open and need to know best freebore for this cartrdge.

Cheers all.

Shaun,

For the purposes of avoiding the donut area, the 180 VLD require the most free bore of any of the common 7mm target projectiles. You'd be best to base your free bore to suit the 180VLD and take what you get for the 168 and any others. Some will be seated only halfway up the neck, but this doesn't seem to be a problem unless you turn the necks ultra thin and are struggling for neck tension. So I would go for the generally recommended free bore figure of 0.220" to suit the 180s. Mine is 0.239" but probably overkill.

Alan

Alan,

Cheers for that mate. I am happy to turn to get rid of donut if needed so thats not much of an issue. But I'm planning on using unturned brass anyway. Ideally id like to have base bullets bearing surface seated at the neck shoulder junction to maximine the amount of neck holding the bullet. But if its not exactly that it shouldnt be an issue. I cant see the 7mm-08AI burning throats like my 6mm's do

I would go with about 0.200 - 0.210 but wouldn't go much shorter for 180's but to honest would look at using 168's with a 0.190 FB.
Matt P

.210 is a good middle ground .200 is best for re chambering old barrels
By the time you run it in and do some load testing you loose a few thou
If you turn your necks properly the donut shouldn’t be a problem IMO
And 168Gr Bergers could be dynamite in that case.
RB

Matt,

Cheers mate. 205-210 seems to be a decent compromise between them. I can't see 10-15 thou making much differnece but I have been known to be wrong a fair bit

I'm spewing the reamer now so will see what PTG recommend and then probably go with around 205-210I think.

Richard,

Cheers mate. I'm liking the 168gr for the shorts for when it's to rough for my 6mm. This could end up being my only F-Open cal if it performs as well as I would like. Otherwise I'll just save it for rainy days.

Shaun with the 7-08AI you shouldn't have any problem with a donut as there is plenty of 7-08 brass available. IMO make sure you can reach the rifling easily with the shortest proj you might use because you can ream it out but you can't put it back.
Steve

Steve, I'm going to be using 308 Palma brass for this rifle. So could still have donut. And yeah. I think I'll be ok with 210 freebore. Seems a good compromise. I don't wanna limit myself to one bullet.