This was a good weekend. Drove my ass down to Canton, MS yesterday to pick up my new rifle, then got to shoot it this afternoon. I started some basic load development (got my seating depth) and sighted in my scope. I've been waiting since beginning of October, so it's nice to see all the moving parts finally come together.

https://imgur.com/a/0JHs6Yt

Caliber is 6mm GT.

ARC Nucleus action
Krieger 1.250" barrel, 26.22" long
APA Fat Bastard gen 3 brake
XTSP Mod 22 trigger
Manners T4 stock
Vortex Strike Eagle 5-25x56 scope
Wheeler high scope rings

I assembled 100 rounds with 35.5gr of H4350 at 0.005" off the lands then brought my arbor press out there so I could bring it in a few thou at a time. I nearly stopped at the second group (6 shots, with the 2 groups in the pics), but shot 2 more groups and I'm really glad I did because I found my depth in the last pic (roughly 0.0225 off the lands).

My load:

35.5gr H4350
Alpha Munitions "Gay Tiger" brass
Berger 108gr Boat Tail Target bullet (I bought 800 of the 108, and I have 1000 of the 105gr VLD as well)
Remington #7-1/2 benchrest primers

GRT says my ideal load should be in the ballpark of 35.1gr of H4350.

My plan is to try and get everything ready to shoot a local(ish) PRS competition next month.

Think that press is stout enough to seat those bullets properly?

The reason I notice is because long ago when I decided to try Wilson dies, the first arbor press I got from Sinclair was not capable of full length resizing. The one I got in exchange handles the job, but only just. Yours is also the press I wish I had had when I was working on SIG Classic line pistol slides and their solid firing pin positioning pins.

Very nice, and the best wishes for your endeavors. Keep us posted. I am always interested in such projects.

The arbor press is fine for my needs. I don't size on it - I have a Lyman Crusher II and (still Wilson) bushing sizer.

I'll upgrade it down the road, but not until it becomes obvious it's a bottleneck. until then I'll keep rocking the freebie.

Sorry if the comment about the press didn't come across as the joke that I intended. It looks like it probably has a couple of dozen times the pressing force as the one I have and which serves my needs.

Nah, it's all good. I'm a little slow today, and a friend was giving me crap about using that instead of a fancy K&M press yesterday.

Nice rifle. 6 GT accuracy is right up there with 6 Dasher, so it should do you well. It will be interesting to see if you eventually go to a spacer in the back of the magazine. I've spoken to 2 competitors with 6 GTs -- both stated that feeding isn't everything that George Gardner touted. Cycle the bolt hard & fast, and eventually they experienced some nose-down jams.

The glass should be fine, but I'd rather see optics that aren't made in China.

Interesting. The one guy I know hasn't had to do anything to his mags to my knowledge and he's on his 3rd or 4th barrel. I'm unused to having a magazine at all, seeing as how I've got Bob Sleds in both of my other bolt guns (another Nucleus in 6.5CM and a 700 in 308). No point fighting a magazine when your ammo doesn't really conform to short action AI mag length standards. I'm going to be getting some MDT polymetal mags when I can afford to.

GT and Dasher had an even playing field in my mind for performance. So that left the memes. I'm a member of the Reddit r/Reloading Discord server, and the Dasher memes got stale after about a week because one of the admins programmed the auto mod bot to post Dasher memes every time someone mentions the cartridge. Or the first of Santa's reindeer.

The GT, though...The Gay Tiger brass sealed the deal for me. I think the GT has a marginal case capacity advantage, but I doubt it's enough to make a massive difference. Hornady making loaded ammo for it is a boon but not much of one.

I too would rather see optics not made in China, but I bought it 6 months ago for this build and I'm using it for now. It was between this or the Arken EP5 5-25x56, which has the same problem in your eyes. The Arken, as we decided, has better glass, but it was such an unknown I wasn't going to slap it on a performance rifle without some vetting, lest we have a repeat of the Great Cheap Cabela's Scope Debacle of 2021 (cheap, crappy scope looked real good, even had half decent glass, but the recoil of 308 actually loosened the internal parallax adjustment, so the scope actually got more out of focus the more you shot it).

ETA: Also I apparently lied. Those were 105BT pills, not 108 like I thought. Still, shoots like a hot damn. I'm going to work up for the 108 and maybe play around with the 40 of these I have left.

This message has been edited. Last edited by: vulrath,

The rifle and the groups are very nice, but what impress me the most is the range. Is that all yours? . I see all the people with their private ranges and I get jelous

Unfortunately, no, it's not mine. We have some family friends just across the state line in Byhalia, MS (about 15 minutes from me in Germantown, TN), and they graciously let me shoot on their land.

They've got a cattle farm, and they own a construction company as well. Their son used to shoot F-Class (F-PR) and PRS, so in 2020 they felled a bunch of trees to bring the 600 yard range out to 1000 yards (just checked the geoballistics app we use; the furthest target is 1053 yards from the bench). (Nowadays he doesn't shoot as much as he wants because he's got a 1 year old and his second is on the way. He does still compete when he can.) He's the one who dragged me into this stuff.

quote:

Originally posted by vulrath:
Unfortunately, no, it's not mine. We have some family friends just across the state line in Byhalia, MS (about 15 minutes from me in Germantown, TN), and they graciously let me shoot on their land.

They've got a cattle farm, and they own a construction company as well. Their son used to shoot F-Class (F-PR) and PRS, so in 2020 they felled a bunch of trees to bring the 600 yard range out to 1000 yards (just checked the geoballistics app we use; the furthest target is 1053 yards from the bench). (Nowadays he doesn't shoot as much as he wants because he's got a 1 year old and his second is on the way. He does still compete when he can.) He's the one who dragged me into this stuff.

A good friend with lot of land is the closet you can get to having your own. I have a friend with 65 acres with his own berm and a 600 yards lane, but he is a 11 hours round trip.

quote:

Originally posted by vulrath:
Interesting. The one guy I know hasn't had to do anything to his mags to my knowledge and he's on his 3rd or 4th barrel.

Feeding (non)issues can be a combo of magazine, feed lips, bullet shape, bottom metal, & others. I have one AI mag that too often does a nose-down jam with FGMM 175 in my 308. But the GT's length is on the ragged edge of reliable feeding in a 308-length mag.

quote:

Originally posted by vulrath:
I too would rather see optics not made in China..... or the Arken EP5 5-25x56, which has the same problem in your eyes.

Buying Chinese goods should be a problem in all American's eyes. And especially in conservative gun owners' eyes. I've purchased Chinese goods in the past, but no longer when alternatives are available.

quote:

Originally posted by vulrath:
Hornady making loaded ammo for it is a boon but not much of one.

I didn't realize Hornady made GT ammo. It's not on their website, but a quick search provided 2 sources. I have a 308 with a barrel on its last legs, with its replacement 308 barrel in the basement. Before buying that 308 barrel, I hoped that either Hornady or Prime might load 6 Dasher or 6BR or 6BRA. No dice -- so I purchased the 308 barrel, then began accumulating components for a 6 Creedmoor build. But with Hornady making 6GT ammo....hmmm, the 308 might go away. Hmmm...Bartlein BB steel barrels in 6mm seem to be out of stock. Hornady match ammo shoots well in my rifles -- in 223, 6CM, 6.5CM, 308. I suspect Hornady 6GT ammo would also shoot well.

quote:

Originally posted by vulrath:
Those were 105BT pills, not 108 like I thought. Still, shoots like a hot damn. I'm going to work up for the 108 and maybe play around with the 40 of these I have left.

There are a number of guys in my area with short-cased 6mm chamberings -- all the guns shoot well. The "Long Range Rifle Discussion" thread here on Sigforum is peppered with examples of 6mm targets. Offgrid shot the Dasher for a long time, then changed to the shorter cased 6BRA. He shows 6mm accuracy potential on thread pages 127, 132, 136, and 137 -- offgrid has boatload of one-hole targets.

The Pmags, I notice, make working the bolt a little more difficult than without them. I'm not going to a Bob Sled yet though. I've been informed that MDT makes a poly mag with steel lips, so I'm going to try and get my hands on one to test run when I get some coin.

Not what I was going for on the made-in-China issue ("open mouth, insert foot"), and also kinda off topic. But. Since it was brought up, let's go. You are absolutely correct. I did actually make a decision to stop buying Chinese scopes and other items, but that didn't happen until after I bought this one.

I fully intend on upgrading it when I can afford to then selling it to offset some of the cost, but in the meantime it lets me use the rifle. From what I've heard the SE don't do the best when dealing with really bad
mirage anyway (I haven't had a problem thus far but also haven't pushed things to the hairy edge); I just don't have $2000 to drop on the Bushnell I was drooling over 4 months ago when I was hunting for AR scopes, nor do I know if it's appropriate for my intended discipline (PRS).

I want to say the scope and rings are the only parts that weren't made in USA, so honestly I'm not doing too badly, especially when compared to a few of my past builds.

Now that we've got that established, let's move on.

quote:

I didn't realize Hornady made GT ammo. It's not on their website, but a quick search provided 2 sources. I have a 308 with a barrel on its last legs, with its replacement 308 barrel in the basement. Before buying that 308 barrel, I hoped that either Hornady or Prime might load 6 Dasher or 6BR or 6BRA. No dice -- so I purchased the 308 barrel, then began accumulating components for a 6 Creedmoor build. But with Hornady making 6GT ammo....hmmm, the 308 might go away. Hmmm...Bartlein BB steel barrels in 6mm seem to be out of stock. Hornady match ammo shoots well in my rifles -- in 223, 6CM, 6.5CM, 308. I suspect Hornady 6GT ammo would also shoot well.

4 groove barrel
5R 1:8 barrel

https://direct.kriegerbarrels.com/

There you go. You're gonna need to get it chambered and crowned but there's a couple of in-stock blanks. Alternatively Krieger has a few 1:8 twist barrels in stock on their site. I assumed you were looking for straight contour, but both Grizzly and Krieger have a few different contours on hand. (I know, I was confused to see Grizzly has barrels, but to be honest that's probably why they still have stock - much like the Spanish Inquisition, nobody expects a machine tool company to carry rifle parts. They're legit; it's where I bought my 30" 308 barrel a couple of years ago.)

I think Hornady has some kind of deal going with GA Precision as they're one of the only 2 manufacturers of brass (other is Alpha Munitions) for GT, and the only way I know of to get it offhand is to go through Mr. Gardner's shop. You can buy the Alpha brass through other places (I've seen them on Blue Collar Reloading, Alpha's site, and a few others) but there's a catch - the Gay Tiger brass I'm using is only available through GA Precision.

At any rate, after much fighting and fiddling with the Wilson dies* I got 100 rounds put together in the same way as my last test, seated to 0.006" from the lands. I'm going to run the same test next weekend (would have been sooner but I work this weekend.) I've heard you have to work pretty hard to make these 6mm cartridges not perform well, but that's not going to stop me from doing what I can to optimize it as much as possible.

* Really, it was fighting with my calipers and my own tired math. I really need to

I forgot about Grizzly. Haven't looked at their site for a long time. With the exception of blanks I've won in matches, recent barrels came from Bugholes.

Krieger makes great barrels. My most accurate 223 AR15 has one, as does my very accurate AR10 in 6.5CM. I would have no problems with a Krieger bolt action barrel, but I've had great luck with Bartlein. I see no reason to change as long as Bartlein blanks are available.

For the 6mm bores, I like a 7.5 twist. I prefer M24 countours. I suspect a 4 groove will work, but I prefer 5R.

The 6mm chamberings are hard on barrels. My recent 6CM has Bartlein's relatively new BB steel -- a harder steel alloy that supposedly increases barrel life by around 50%. My local 'smith said BB steel feels harder when cutting the chamber, and a sharp reamer is necessary. I don't have enough rounds on the BB barrel to know its longevity. However, this BB steel barrel gave me the fastest barrel break in that I've experienced to date. I don't recall a barrel that has lower levels of carbon fouling. Its MV stabilized sooner than others I've used -- from any brand.

Time will tell if BB steel is all it's supposed to be, but for the moment I will wait for BB blanks to be back in stock before I'd consider converting the 308 to 6GT.

Hmm. I'm interested in hearing how the proprietary alloy holds up over the long term. It might be worth buying a blank and having it spun up as a prefit to stick in the corner (just got my barrel vise set up on the reloading bench, too) for when it's time to swap.

I am fully aware of how difficult the 6mm (and to be honest, 6.5mm chamberings, too) are on the barrel. I went from 308 (barrel life in the tens of thousands usually) to 6.5 Creedmoor (estimated 3500 or so round barrel life) to 6 GT (which my buddy is getting an estimated 2500 rounds from). He rocks the Berger 109HT on the slow side for better barrel life, it's part of why I like hand loading for these oddball cartridges. I'm sure if I were to optimize based on speed I'd have a significantly shorter barrel life.

I'd have preferred a 7.5 twist 5R barrel myself, but I had to work with what I could get. Back in September 7.5 twist blanks were nonexistent from the usual scumbags so I compromised with a 7 twist 4 groove to get the project off the ground. I don't regret my decision one bit, though I'm going to go in a different direction when I replace it and get what I originally wanted.

This message has been edited. Last edited by: vulrath,

quote:

Originally posted by vulrath:
I'm interested in hearing how the proprietary alloy holds up over the long term.

I cruised sites for updates and not much is going on. However, Bugholes and Frank Green of Bartlein state that BB steel barrel life actually may be closer to double that of regular stainless steel.

quote:

Originally posted by vulrath:
I went from 308 (barrel life in the tens of thousands usually) to 6.5 Creedmoor (estimated 3500 or so round barrel life) to 6 GT (which my buddy is getting an estimated 2500 rounds from).

Tens of thousands of rounds through a 308 is not in the same type of use or accuracy league as these other round counts. As I see it, tens of thousands of rounds in a 308 barrel equates to keyhole strikes at distance.

It's my understanding that F-class guys will pull 308 barrels around 4k rounds. They're looking for holding verticals of less than 1/2 MOA, and their loads are pretty stout.

A 308 in steel-match-type shooting with 1/2 MOA requirements is maybe 5-6k rounds. Around 5k rounds on my 308 Bartlein, my 'smith put a new rail on the receiver. I asked him to take a quick look at the throat while he had rifle apart. He said the throat looked a little rough and the lands were showing noticeable erosion. Meaning that the barrel was nearing end of PRS-accuracy-level life. With a new rail & scope, I shot a fair amount of long-ish range 5-round groups to assess the barrel. I did get quite a few decent results -- holding verticals of .4 to .6 MOA at distances of 500-750 yards. The best that I made notes on was 2.25" vertical at 660 yards with FGMM 175, or roughly 1/3 MOA. The horizontal variation was almost the full width of an IPSC target, but that's part of shooting in variable crosswinds with a 308.

I believe my 308 barrel is just over 6k rounds now. I figure it could go tits up an any moment. When groups open up to 3/4 MOA or I start seeing low flyers at distant targets, I'm pulling the barrel. The barrel is currently struggling with Hornady 168 ELD-M ammo, which tells me the lands are getting worse. I find that ELD-M bullets demand a good throat and minimal jump. The barrel still does fine with FGMM 175 and Hornady 168 AMax -- ammo that seems to tolerate jump well.

My 'smith says that if 1 MOA is acceptable with a 308, then 9-10k rounds on a barrel is in the normal realm. That accuracy level won't work for me.

I pulled my first 6.5CM at just over 3200 rounds. I experienced a few low flyers on targets of 800-1000 yards at a match. I rarely yank shots low, so that was a telling sign. My 'smith said throat erosion on that barrel was quite bad, and the bullet had a jump of over an inch to the lands. I pulled my second 6.5CM barrel at just under 3000 rounds. The barrel was still shooting well, but my next match was an ELR event and I didn't want wonky shots at 1800 yards. My 'smith said this barrel wasn't quite as bad, but figured that MV would be dropping off soon.

IIRC the local 6 Dasher guys were getting 2200-2600 rounds per barrel. 6 BRA bumping up against 3000. Based on other 6CM and 6x47 guys, I'm going in to 6CM with an expectation of 1800 rounds for a regular SS barrel. If Bartlein's BB steel barrels double that life, I'm good.

My memory isn't to be trusted then. I remembered 10,000 as "tens of thousands." My needs have also changed over the years.

I'm trying to get out this weekend to play with the 108BT.

Please keep me posted on your real world experience with the BB steel.

https://imgur.com/a/YoPTilA to
As a courtesy I'm leaving it as a link. Pic's way too large.

I'll take them apples.

Final load:

Alpha cases
6mm Berger 108BT
35.5gr H4350
Unknown seating depth (set it on my first adjustment without a caliper)

I'm ecstatic with the performance.

Nice!

Getting there.

Definitely. I think a large part is me finally mounting the bipod. I've got a dovetail rail for photography held on with tee nuts and 1/4-20 bolts so I can swap one bipod across 3 rifles.

I'm taking notes about my seating stem depth so I can replicate it if I change it.

I've got another stem assembly on hand for the 105VLD I've got as well.

I haven't chrono'd it yet because the Labradar I was going to borrow fell through, but I'm trying to stay under 2900 FPS to increase barrel life (not going to be by much I know, but every little bit helps).