6.5 CM long barrel 28" question?

[PNW Gasser]

I've been reading up on the 6.5 CM and I'm trying to find some info on the longer barrels (26-28") and how they perform in the AR guns. I plan on mostly shooting target with occasional hunting.

The 6.5 x284 Norma would be great, aside from the short barrel life and it not working in the AR's.

Seems like the 140 grain bullets do exceptionally well at range at the higher velocities. Would a 28" barrel improve my chances of (safely) hitting 2900+ with a 140 grain bullet?

Haven't found anything here from someone shooting a 28" 6.5 CM gas gun and I figure there are reasons, I just don't know what they are.

 

[Inline6]

Re: 6.5 CM long barrel 28" question?

I have a boltgun that I Melnoited the barrel on, I am hitting 2900fps with factory 140 A max ammo out of a 24" barrel.

I also have about the same setup nonmelnoited and it hits 2795 same lot about 100rds more down the tube.

FWIW.

 

[PNW Gasser]

Re: 6.5 CM long barrel 28" question?

Did a little reading on the treating, thanks for mentioning it.

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2653056

The shooters in that thread were also reporting higher velocities, albeit about half what you are getting.

How many rounds did you run before you had it Melnoited? My thinking being that I could break it in at 28", test accuracy and velocities then get it Melnoited. As I understand it, once the barrel has been treated it can't be machined.

So many variables (myself being the biggest) I have a lot to learn here.

 

[Redmanss]

Re: 6.5 CM long barrel 28" question?

What is the maximum range you're looking to push it to? Also, why do you feel the need to have a gas gun that weighs that much, is that long and cumbersome, only to squeeze out another 50ish FPS over a 24" barrel?

I can't say if it would have any negative effects on functioning as I've never heard of anyone running anything longer than 24".

 

[PNW Gasser]

Re: 6.5 CM long barrel 28" question?

Probably 1k on the range, 6-800 hunting (small game, varmints) I don't know that I want that much barrel. I just want to get the most I can out of the 6.5 CM should I go this route. If that meant running a 20" so be it.

No need for any extra weight either, but if that's what it takes I don't mind a few extra pounds.

If having a 28" is only going to gain me a potential 50 fps over a 24" then I see no point in a 28"

The only possible upsides I could think of would be better stability and maybe the chance to have it re-cut for a little more life.

Mostly I'm trying to find out why it's not done on gassers yet not altogether unheard of on the bolts.

 

[Redmanss]

Re: 6.5 CM long barrel 28" question?

For me I don't want my projectile to have that much dwell time in the barrel after it passes the gas port engaging the next part of the cycle of operations. In my opinion the minor gain in velocity is outweighed by the drawbacks. 28"+ barreled bench and F-Class bolt actions are one thing, but it's a different story for a rifle that is going to see field time.

For reaching 1k, you can easily achieve that above transonic velocity with a 20-24" barrel while both saving on weight and also keeping a weapon that is easier to carry and manipulate. You're not going to recut a precision gas gun barrel without having to also change up the gas tube length and running into functioning issues, so that is a moot point.

Just select a quality barrel and builder for the rifle as they don't cost that much anyhow when you really come right down to it. If you can afford to burn out a 6.5CM barrel, you can afford to replace it.

 

[Inline6]

Re: 6.5 CM long barrel 28" question?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: PNW Gasser</div><div class="ubbcode-body">Did a little reading on the treating, thanks for mentioning it.

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2653056

The shooters in that thread were also reporting higher velocities, albeit about half what you are getting.

How many rounds did you run before you had it Melnoited? My thinking being that I could break it in at 28", test accuracy and velocities then get it Melnoited. As I understand it, once the barrel has been treated it can't be machined.

So many variables (myself being the biggest) I have a lot to learn here.

</div></div>

It was new. If it’s built by a good smith they are going to check the barrel out before they put all that time in it. Some things can not be seen, with that said talk to the barrel manufacture let them know your plans (see what they say about warranty). If it does not shoot for some crazy reason it is not going to be from the melonite.