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.

 

[Av8radam]

I’ve had great results with Sierra 85g bthp out of a 243. Old school, but they shot great. DRT.

 

[diggler1833]

I’ve had great results with Sierra 85g bthp out of a 243. Old school, but they shot great. DRT.

My neighbor kills all of "my" #1 bucks each season with a lowly .243 and an 85gr soft point.

It is an amazingly effective combo.

 

[TheBigCountry]

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.

Don’t you DARE knock gas station sushi

Just like the omelet MRE

 

[TheBigCountry]

Has OP looked at the 6ARC as well? I’ve been impressed with the few I’ve seen

 

[KyleR1985]

I punched a factory Howa mini 6ARC barrel with a dasher reamer. Cut the barrel to 16”.

I get 2800 with 95tmk’s, and 2700 with 108eldm.

It feeds flawlessly from 450bushmaster mags that legacy has in stock. Working on a mag box for it with JO.

The rifle weighs under 7.5lbs with a swfa3x9 and DD wolf hunter. Stockys VG.

The GT was a little too long to fit in the mini action. Dasher seems to be the most powder that you can cram in there. But should give you an idea of the floor for you on velocity.

 

[The blind marksman]

I am thinking of doing a near similar build for next season (fall 2026) I want a yote/
WT deer rifle is easy to shoot and something that the Mrs. can build confidence on. Anyone have experience with 6GT in a Carbon 6 barrel or just carbon 6 to begin with?

 

[4O6shootist]

I am thinking of doing a near similar build for next season (fall 2026) I want a yote/
WT deer rifle is easy to shoot and something that the Mrs. can build confidence on. Anyone have experience with 6GT in a Carbon 6 barrel or just carbon 6 to begin with?

I wouldn't touch a carbon6 prefit. Their barrels are decent but their in-house smitin is shoddy at best. Lots of poor threads, poor headspace, ugly machining. The barrels are mcgowan blanks, as they're a sister company.

A light contour steel in a short length will finish within 4-6oz of a carbon and be half the price.

 

[The blind marksman]

I wouldn't touch a carbon6 prefit. Their barrels are decent but their in-house smitin is shoddy at best. Lots of poor threads, poor headspace, ugly machining. The barrels are mcgowan blanks, as they're a sister company.

A light contour steel in a short length will finish within 4-6oz of a carbon and be half the price.

I would just get a blank and have one of the gunsmiths I work with chamber and thread everything. The other option is I have a proof barrel blank ordered and have it spun locally as well.

But go to know about there in house smith. I will definitely not be doing any pre fits with them

 

[smarcus]

Just a data point but I get 2750 from factory 6mm Creedmoor out of a 16.5 inch Proof CF barreled Defiance anTi.

 

[AMG04]

I recently evaluated the 6BR, 6 Dasher, 6GT, 6x47 and the 6CM for a short, handy rifle for my wife and kids.

I went 6CM because I could burn a little more powder and regain some velocity (useful for bullet expansion). I also had way more powders in the medium burn rates. I only have N140 and H4895 for the BR size cases.

Here is some data I analyzed across all the powders I have for 6CM, 16" and 18". As others have said, the 2740 is optimistic from a 16, but not an issue in the 18. This is with 108 Bergers and a few lighter bullets for lighter recoil loads.

These are not max loads, but align with the highest OBT node I could get to with out going over 62k psi.

16"

18"

Looking at the average across all powders the 16" barrel only has 0.5" more wind drift and 1.5" more drop at 300 yards. I can't shoot the difference so I went as short and maneuverable as I could.

 

[The blind marksman]

I recently evaluated the 6BR, 6 Dasher, 6GT, 6x47 and the 6CM for a short, handy rifle for my wife and kids.

I went 6CM because I could burn a little more powder and regain some velocity (useful for bullet expansion). I also had way more powders in the medium burn rates. I only have N140 and H4895 for the BR size cases.

Here is some data I analyzed across all the powders I have for 6CM, 16" and 18". As others have said, the 2740 is optimistic from a 16, but not an issue in the 18. This is with 108 Bergers and a few lighter bullets for lighter recoil loads.

These are not max loads, but align with the highest OBT node I could get to with out going over 62k psi.

16"
View attachment 8751974

18"
View attachment 8751972

Looking at the average across all powders the 16" barrel only has 0.5" more wind drift and 1.5" more drop at 300 yards. I can't shoot the difference so I went as short and maneuverable as I could.

I assume that barrel is the 1:7.5 twist?
I am between a 108 gr Berger and the 100 gr. Sierra TGK as I have had great expansion with the Sierra. But no experience with the berger

 

[The blind marksman]

I recently evaluated the 6BR, 6 Dasher, 6GT, 6x47 and the 6CM for a short, handy rifle for my wife and kids.

I went 6CM because I could burn a little more powder and regain some velocity (useful for bullet expansion). I also had way more powders in the medium burn rates. I only have N140 and H4895 for the BR size cases.

Here is some data I analyzed across all the powders I have for 6CM, 16" and 18". As others have said, the 2740 is optimistic from a 16, but not an issue in the 18. This is with 108 Bergers and a few lighter bullets for lighter recoil loads.

These are not max loads, but align with the highest OBT node I could get to with out going over 62k psi.

16"
View attachment 8751974

18"
View attachment 8751972

Looking at the average across all powders the 16" barrel only has 0.5" more wind drift and 1.5" more drop at 300 yards. I can't shoot the difference so I went as short and maneuverable as I could.

I assume that barrel is the 1:7.5 twist?
I am between a 108 gr Berger and the 100 gr. Sierra TGK as I have had great expansion with the Sierra.

 

[4O6shootist]

I put an 18in proof barrel in 6cm on my sig cross. Running some 105gr midsouth factory seconds, believe they're a tipped Hornady bullet(black tip) at 2860 with 41.3gr H4350. Shoot really well, 10in plate at 850y on Sunday was fairly easy. My 22in 6gt runs the similar velocity with 109 Bergers using rl15.5.

Going with a sub 20in barrel the case capacity of the creed makes sense to get back your velocity, however you should pay attention to calculated amounts of unburnt powder as you get sub 18in. That can cause some es issues and vertical out at distance. This is where the efficiency of the gt helps. I'm not stepping in either of these loads, they'd like go another 100+ fps before pressure, but they shot really well where I landed.

I don't doubt the chamber psi is up there, but with lapua and alpha, you just don't see it.

 

[mark5pt56]

I recently evaluated the 6BR, 6 Dasher, 6GT, 6x47 and the 6CM for a short, handy rifle for my wife and kids.

I went 6CM because I could burn a little more powder and regain some velocity (useful for bullet expansion). I also had way more powders in the medium burn rates. I only have N140 and H4895 for the BR size cases.

Here is some data I analyzed across all the powders I have for 6CM, 16" and 18". As others have said, the 2740 is optimistic from a 16, but not an issue in the 18. This is with 108 Bergers and a few lighter bullets for lighter recoil loads.

These are not max loads, but align with the highest OBT node I could get to with out going over 62k psi.

16"
View attachment 8751974

18"
View attachment 8751972

Looking at the average across all powders the 16" barrel only has 0.5" more wind drift and 1.5" more drop at 300 yards. I can't shoot the difference so I went as short and maneuverable as I could.

Holy cow! I have a 6ARC build in right now, this thing is going to be a breeze to shoot.