.22 GT

[Juan_ID]

Both of my current .22 GT barrels are 7” twist Bartlein 5Rs with a .218” bore. I went with 7” twist because I wanted to ensure stability with 88gr ELDs. A bunch of folks go with a .219” bore because in flight bullet failures seem to happen less with the .219” bore, but so far, I’ve had no failures.

John

I recall seeing something about 3r not being the best for this caliber, I’ll have to call preferred and see what they use for the bore and if they’ve noted any issues with the 3r and 7 twist.

 

[Bwhntr]

I recall seeing something about 3r not being the best for this caliber, I’ll have to call preferred and see what they use for the bore and if they’ve noted any issues with the 3r and 7 twist.

I have a preferred 22GT on order so I’d be interested in this. As well as what freebore they are using. I went with a 1:7.5

 

[Juan_ID]

I have a preferred 22GT on order so I’d be interested in this. As well as what freebore they are using. I went with a 1:7.5

They use a .219 bore and a 169 freebore, along with a .255 or .260 neck. This is all beyond what I’ve really looked into as I’ve only ever re-barreled one other rifle but plan on loading up a dummy round and checking neck diameter as I’d likely use necked down hornady 6gt brass.

 

[Hondo64d]

I recall seeing something about 3r not being the best for this caliber, I’ll have to call preferred and see what they use for the bore and if they’ve noted any issues with the 3r and 7 twist.

I’m not familiar with 3R.

John

 

[Juan_ID]

I’m not familiar with 3R.

John

The 3r aside do you see any reason to go 7.5 instead of 7 twist or vise versa? Primary projectile would be 88 eld’s and maybe a side of 77gr tmk’s.

 

[Hondo64d]

The 3r aside do you see any reason to go 7.5 instead of 7 twist or vise versa? Primary projectile would be 88 eld’s and maybe a side of 77gr tmk’s.

A lot of folks go with 8” twist in hopes of slowing bullet RPM enough to avoid bullet blow up. The cost is a little less stability resulting in a little less BC. I don‘t have any regrets on going with 7” twist, but my barrels have a low round count and the throats are still in pretty good shape. Remains to be seen what will happen as the round count increases. I went with .218 5R bores because that was what was readily available. If I had enough patience to wait, I would order .219” bores with 5R rifling profile. Bartlein says the 5R rifling is easier on bullet jackets than conventional rifling. I would stay with the 7” twist but could change my mind if I start blowing up bullets later on.

John

 

[Juan_ID]

A lot of folks go with 8” twist in hopes of slowing bullet RPM enough to avoid bullet blow up. The cost is a little less stability resulting in a little less BC. I don‘t have any regrets on going with 7” twist, but my barrels have a low round count and the throats are still in pretty good shape. Remains to be seen what will happen as the round count increases. I went with .218 5R bores because that was what was readily available. If I had enough patience to wait, I would order .219” bores with 5R rifling profile. Bartlein says the 5R rifling is easier on bullet jackets than conventional rifling. I would stay with the 7” twist but could change my mind if I start blowing up bullets later on.

John

Bullet blow up is what I am wanting to avoid, but also wouldn’t mind maximizing the bc and barrel life. Though I don’t know how much difference going 7.5 twist would make instead of 7. But again most the technical stuff is beyond my knowledge. When you say low round count, what are you at? I have never shot a barrel out but looking to do so with this one.

 

[Hondo64d]

Bullet blow up is what I am wanting to avoid, but also wouldn’t mind maximizing the bc and barrel life. Though I don’t know how much difference going 7.5 twist would make instead of 7. But again most the technical stuff is beyond my knowledge. When you say low round count, what are you at? I have never shot a barrel out but looking to do so with this one.

I don’t keep a log of rounds fired, but guesstimate about 200 rounds each.

John

 

[willfrye027]

Bullet blow up is what I am wanting to avoid, but also wouldn’t mind maximizing the bc and barrel life. Though I don’t know how much difference going 7.5 twist would make instead of 7. But again most the technical stuff is beyond my knowledge. When you say low round count, what are you at? I have never shot a barrel out but looking to do so with this one.

FWIW, in a 1:7 creed (.219, 5r) I started blowing up 88eldm somewhere around 400 rounds. I was not pushing hard 3050-3080fps on 26” barrel. Something was a little off with the barrel to be fair, that was about max before pressure signs. Pulled that barrel when every 1:10 would go poof..will spin it back on at some point with a more durable bullet.

Personally I’d go 7.5 on my next barrel shooting eldm. Also have not detected a BC decrease that I could detect out to 1000 yards with my current 1:8 barrel shooting 88eldm. Drops are lining up as expected

 

[Juan_ID]

FWIW, in a 1:7 creed (.219, 5r) I started blowing up 88eldm somewhere around 400 rounds. I was not pushing hard 3050-3080fps on 26” barrel. Something was a little off with the barrel to be fair, that was about max before pressure signs. Pulled that barrel when every 1:10 would go poof..will spin it back on at some point with a more durable bullet.

Personally I’d go 7.5 on my next barrel shooting eldm. Also have not detected a BC decrease that I could detect out to 1000 yards with my current 1:8 barrel shooting 88eldm. Drops are lining up as expected

This is good to know, I’ll do a little more research and see what I end up with. Thank you

 

[Juan_ID]

Anything new from the guys in this thread that are already shooting the GT? I should be getting close on my barrel, ended up ordering a 20” 1-7.5 twist.