Rebarreling a GAP-10 to 6mm or 6.5mm - which one?

[ReaperDriver]

I'm planning on rebarreling a .308 GAP-10 to either a 6mm or 6.5mm caliber. Main use will be Precision gas gun tac matches as well as some 1000+ yd steel for fun. I currently have a Bolt gun (AI AT) in .260 Rem and love the cartridge. But am hearing a lot about the smaller bullets like 6 Creedmore and such. What are the pros and cons of each? I assume the 6mm will be a bit lighter on recoil, though the .260 is pretty tame already. But that's in a 14lb rifle. I'm concerned about not having a barrel burner, but not sure if there is much difference between a 6 CM and a 6.5CM or .260 in terms of barrel life.

Also is the 6mm capable of going beyond 1K? I often shoot steel at 1300-1600 with the 260, so don't want to give up too much range. But again, primary use would be gas gun Tacitcal/Precision matches - and most of ours are 200-900 yds and everything inbetween.

Any thoughts, pros/cons, suggestion, other calibers that I have not mentioned, etc are most welcome. Thanks in advance.

 

[diggler1833]

The 6mm rifles are going to give you anywhere from 1/2 to 2/3 the barrel life of the 6.5mm ones...depending on how hard each is ran. I've not used the 6mm Creedmoor, so take it for what it's worth, but most of the stuff I've seen out there is looking like 1,500 rounds versus 2,500 to 3K for the .264 diameter stuff. I have a lot more experience with the .260 Remington myself.

 

[DavidAR10]

If you need 6mm in a LARGE Gasser... you need a 6mm Bolt even more.
Along with dedicated 81 & 155 MikeMikes.

6mm ARC in a standard AR package over a 6mm CM... almost any day.

BUTT!!! what the heck do I know?

Best to you.

BTW, Frank is a terror with only 18" of pipe in 6.5 CM in heavy winds at @ 1200yds.

 

[nickw]

The 6mm rifles are going to give you anywhere from 1/2 to 2/3 the barrel life of the 6.5mm ones...depending on how hard each is ran. I've not used the 6mm Creedmoor, so take it for what it's worth, but most of the stuff I've seen out there is looking like 1,500 rounds versus 2,500 to 3K for the .264 diameter stuff. I have a lot more experience with the .260 Remington myself.

I smoked a Bartlein 6Creed barrel in 850 rounds shooting it in PRS matches. Most pull them by 1000. I would go 6.5 to get the better barrel life.

 

[STI_1911_Guy]

I would be hesitant myself putting a 6mm creed in a gasser just due to barrel life. Erosion happens so quickly with the 6mm creed and the AR's purpose to me is a higher volume of fire. Just my opinion.

 

[GUNNER10]

While I am sure 6mm is more effeciant, I am not sure that I would do one in a large frame AR. Personally while I reload, most of my match ammo, I like the idea of have decent match ammo available commercially. Since i have been working overseas, I do not have the time to reload when i am home on leave, so having something like American gunner available in 6.5cm is awesome.

Now if I was state side and could put the time into reload, I would consider a 6mm

 

[ReaperDriver]

Good stuff guys, thanks. I think I'm going to stay with the .260 Rem for my Upper build. I don't want to have to go through barrels that quickly with a 6mm.

 

[SFree]

If you need 6mm in a LARGE Gasser... you need a 6mm Bolt even more.
Along with dedicated 81 & 155 MikeMikes.

6mm ARC in a standard AR package over a 6mm CM... almost any day.

BUTT!!! what the heck do I know?

Best to you.

BTW, Frank is a terror with only 18" of pipe in 6.5 CM in heavy winds at @ 1200yds.

Frank who?... The closet gas gun guy?

 

[DavidAR10]

Frank who?... The closet gas gun guy?

 

[ReaperDriver]

I would be hesitant myself putting a 6mm creed in a gasser just due to barrel life. Erosion happens so quickly with the 6mm creed and the AR's purpose to me is a higher volume of fire. Just my opinion.

No that makes perfect sense, thank you!

 

[Qazwsx]

Staying with 260 for both would be caliber efficient for you imo

 

[ReaperDriver]

Staying with 260 for both would be caliber efficient for you imo

Yep, already done. Just ordered all the parts to build a complete JP upper in .260. The guys at JP were amazing to work with and super helpful. I can't wait to get this put together and get it out banging some long range steel.

 

[deersniper]

I smoked a Bartlein 6Creed barrel in 850 rounds shooting it in PRS matches. Most pull them by 1000. I would go 6.5 to get the better barrel life.

How’d you know it was dead ?