Need Input 6mm AI or 6.5 WSM?

[arnygollott3]

First off, I am well aware of the low round count that could be expected from BOTH of these cartidges but would enjoy input on which one MIGHT offer slightly better barrel life.

This project rifle would NEVER see competition, varmint town, or fast follow up shot use...so I can just about eliminate heat between shots.
Mostly a bench gun that might see some VERY limited use as a hunting rifle from Shooting Houses so weight is not a HUGE concern but will be avoided if it can easily be done.

I want to shoot the longest, highest BC bullets I can for either round so action/DBM length will be a high priority for me. I do not want a barrel any longer than 26" and it will be fluted and threaded for a break.

This will be a 'mid grade' budget build...not 'el cheapo' but not premium because I want to be able to use it in the field and not be totally focused on being 'careful' not to scratch it!

I am thinking Savage Stainless Action with Accutrigger. I like the Accutrigger. I am thinking Broughton for the barrel.

I want/like adj stocks...LOP and Cheek Piece. McMillan, Manners, and McRees are all options but still open minded here...

If I went with 6mm AI it would be on the long action so I can difinitely maximize COL. What mag system is best for this action length?

What mag system in WSM is best for LONG bullets, or would 6.5mm bullets even be an issue in most DBM WSM systems?

Now, for the hard part...which cartridge to build for?

I would like to acheive 3/4 MOA or better if possible...

6mm 115 DTACS at 3200 with BC of .585

6.5mm 140 Bergers at 3200 with BC of .610

I have no need for varmint or light weight bullets, the only hunting would be on medium game so 'tough' bonded type hunting bullets would be used in those cases...advantage 6.5 WSM with more energy on target with a better selection of medium game type bullets.

Punching paper with the 6mm AI would be easier on the shoulder and cheaper to load for as well as having much more load data available...

Please...tell me what you think!

 

[wnroscoe]

Re: Need Input 6mm AI or 6.5 WSM?

I'd look at the 6.5 RSAUM. While the 6.5WSM would be a good one, you'll hit pressure before you get the case full of powder. The 6.5 RSAUM should give the same velocities as the 6.5WSM with less powder and a higher load density ratio. I shoot the 7/300wsm and love it but, I still have room in the case. I've seen a 7mmRSAUM give the same velocity as mine with the same bullet, less powder.

 

[arnygollott3]

Re: Need Input 6mm AI or 6.5 WSM?

6-284 is also a possibility...

 

[arnygollott3]

Re: Need Input 6mm AI or 6.5 WSM?

Anyone out there with some experience with one of these wildcats that can help me make this decision...?

 

[pdd614]

Re: Need Input 6mm AI or 6.5 WSM?

I think the g1 bc of the 115 dtacs is only .540. with a g7 bc of .276. might help sway your decision a bit.

you got it about right on the berger 140. g1 bc of .612 and a g7 bc of .313.

 

[arnygollott3]

Re: Need Input 6mm AI or 6.5 WSM?

Is that .540 number the 'old' open nose style or the newer improved closed nose type?

 

[pdd614]

Re: Need Input 6mm AI or 6.5 WSM?

I think it is the old version, but i'm not sure. I got the bc numbers from applied ballistics for long range shooting. I think Brian Litz would be the better person to ask since he did all the testing.

 

[BryanLitz]

Re: Need Input 6mm AI or 6.5 WSM?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Is that .540 number the 'old' open nose style or the newer improved closed nose type? </div></div>
It's the old (unpointed) type. I haven't tested the new ones. I think the new pointed DTACS are about ~3% better, which is a typical improvement for pointing.

I would recommend against a 6-284. Just too much burn for a bore that small. Almost every time I hear about the 6-284, the context is how to prevent the inevitable bullet failure. I talked to a guy once who did a 22-284; no chance.

It's tempting to hot rod those small caliber heavies, but the reality is they just don't hold up in the long run, sometimes even in the short run. It's best to be satisfied with the nominal velocities you get from the medium capacity cases or go up in caliber if you're serious about <span style="font-style: italic">reliable</span> improved ballistics.

-Bryan

 

[arnygollott3]

Re: Need Input 6mm AI or 6.5 WSM?

Bryan, good info, thank you!

I keep getting drawn towards the 6mm AI or even the 6mm Crusader that is under development here on the Hide...

I understand I will be giving up high rate fire for the top 'usable' muzzle velocity that I want with any of these cartridges, if I get 1000 rds I would be ok, 1500 I would be happy. With my style of shooting and from what I have read it seems I can get that barrel life.

 

[pdd614]

Re: Need Input 6mm AI or 6.5 WSM?

Thanks for chiming in Bryan. Your book has become my "go to" source for understanding bc.

 

[gmbjr]

Re: Need Input 6mm AI or 6.5 WSM?

I built a 6.5wsm for long range deer hunting. Rifle sports a Pac-Nor 3 grove bbl, 27" long. I'm getting 3200fps with 140 Bergers and RL25. I had to use standard rifle primers (210m). I had to try several powder, primer, and brass combos to get one that worked without pressure.

Chris Mathews and LSR has a pretty good handle on the 6.5WSM if you go that direction.