Light- short 6GT

[VandelayIndustries]

Looking to build a hunting/ long range gun for the kids/wife. I was thinking 6GT because it’s mild recoil, can put deer down, also the barrel life is decent, I don’t want to swap barrels every 1200 rounds. Was thinking 16” barrel for easier handling, with a 108gr bullet looks like it should hit 2750fps. Ballistics are very similar to a 6.5cm running 140’s in that range. Is there a better cartridge I’m missing that would fit?

 

[4O6shootist]

I think 2750 with accuracy is possibly being optimistic. Shortest 6gt I have is 22in, using 109 Bergers and TS15.5(dbl based high energy powder that runs 30-50fps VS varget), I went up to 35.5gr(psi signs on primer, very flat, slightly cratering) 2930fps. Dropping a half grain for safety was 2880, but it shoots the best at 2840-2850. I could possibly switch to H4350 for more speed, or go to a 105hyb.

I think from 22" to 16" you can expect to see 30-35fps loss per inch. So a 16in would be topping out at or near pressure around 2780-2800 fps. If you're referring to the 108 eldm, that bullet has a lot of bearing surface that'll increase pressure as well. I'd recommend a 170fb for that bullet personally.

I have 18in 6cm and 22cm as well. From what I've observed using conventional powders(not rl26 or N560 crack) the 22/6 GT at 22in compares very similar to the 22/6cm at 18in lengths where psi/velocity come in line.

 

[BoilerUP]

I get 2800fps with a 20" Dasher and 108s.

A 16" 6GT *might* see 2750, but 2700 is prob more realistic.

 

[4O6shootist]

I just browsed the 6gt Facebook group, but there are some guys running the low 2800s node from 16-17" barrels. Alpha brass is very resistant to bolt lift but you really gotta look at primers for pressure signs with alpha ocd brass. They'll tell way sooner than bolt lift.

Supposedly sierra is doing a run of the 95tmk in next couple months(they've been saying this since Jan) and that bullet kills very well. You'll be able to get 200fps more than a 108gr as the bearing is very short. They'd do the trick to 600y I'm sure.

 

[CStroud]

I built this exact setup for what you're wanting a couple years ago and absolutely loved it. I killed a pile of stuff around the farm with it, and it was a joy to handle and shoot. 16" proof chambered by Altus on an Impact NBK. I had it feeding from AW's fairly consistently but not good enough I'd run it in a match. Don't remember the chrono numbers off hand, but I do not remember being disappointed with factory 108's.

 

[diggler1833]

I just browsed the 6gt Facebook group, but there are some guys running the low 2800s node from 16-17" barrels. Alpha brass is very resistant to bolt lift but you really gotta look at primers for pressure signs with alpha ocd brass. They'll tell way sooner than bolt lift.

Supposedly sierra is doing a run of the 95tmk in next couple months(they've been saying this since Jan) and that bullet kills very well. You'll be able to get 200fps more than a 108gr as the bearing is very short. They'd do the trick to 600y I'm sure.

I trust guys boasting about their speed data on the internet like I trust gas station sushi. However, thanks for letting me know about the 6GT FB page... I'm going to go and check it out.

I think that a 95gt TMK would be pretty sweet out of a GT as well if Sierra actually brings one to market. I farted around with a 95gr NBT in my GT, just to see how it would do, and I got in the 3,050 range out of a 27" barrel and ~.6 MOA. I don't remember the exact velocity, but I think I posted it in the 6GT load data page in the reloading subsection. I was actually going to post about the 95gr NBT for this guy's build until I saw your mentioning of the 95gr TMK.

******

OP: I'd definitely be looking at lighter bullets (<100gr) for this shorter barrel as I'm assuming the hunting ranges would be less too. Stuff like the 90gr ELD-X, 95gr Berger, 95gr NBT, or 95gr LRX ought to get you to 400 yards still with pretty good efficiency in killing.

 

[VandelayIndustries]

I trust guys boasting about their speed data on the internet like I trust gas station sushi. However, thanks for letting me know about the 6GT FB page... I'm going to go and check it out.

I think that a 95gt TMK would be pretty sweet out of a GT as well if Sierra actually brings one to market. I farted around with a 95gr NBT in my GT, just to see how it would do, and I got in the 3,050 range out of a 27" barrel and ~.6 MOA. I don't remember the exact velocity, but I think I posted it in the 6GT load data page in the reloading subsection. I was actually going to post about the 95gr NBT for this guy's build until I saw your mentioning of the 95gr TMK.

******

OP: I'd definitely be looking at lighter bullets (<100gr) for this shorter barrel as I'm assuming the hunting ranges would be less too. Stuff like the 90gr ELD-X, 95gr Berger, 95gr NBT, or 95gr LRX ought to get you to 400 yards still with pretty good efficiency in killing.

I’m open to shooting lighter bullets, as long as they’re still in the .5’s for G1, gain a little speed back too, that’d be a win. Now the fun part begins.. the build

 

[VandelayIndustries]

Is the 6GT a .478 bolt face? I was thinking it was .473.

 

[diggler1833]

Is the 6GT a .478 bolt face? I was thinking it was .473.

You are confusing bolt face and case head diameters. .478 bolt face, .473 case head.