6gt

[Niles Coyote]

109 Hybrid's seated for .065" jump, 32.0gr Varget in Alpha brass and FGMM primers, 2841fps, 5@500 10@700
Straight Jacket Armory 26" proof with a .170 alpha reamer. This ought to work well at our first Michigan regional match for 2023 next weekend.

 

[lennyo3034]

Sorry if I missed this but what size bushing is everyone using for alpha brass?

 

[4O6shootist]

Sorry if I missed this but what size bushing is everyone using for alpha brass?

I'm using 267 redding, gives me 266-2665 after sizing and loaded is 269. I do not mandrel or expand, just seat a bullet. Gives me half moa groups at 700y, and 10 shot groups in the 3s at 100y. Es is mid to high teens generally.

 

[CK1.0]

Sorry if I missed this but what size bushing is everyone using for alpha brass?

I'm using a .266" custom-honed FL die followed by a .241" mandrel for the "Gay Tiger" headstamped Alpha cases that were available from GAP. Works beautifully.

 

[ghostrider_OneOne]

Varget, N150, TS15.5, H4350, RL16, it don't matter, the gt shoots as long your reloading practices are sound. 4166 works too but only if you're content with speeds mid 2800s and lower, but in that case you should be shooting a br based case.

I'm not disagreeing with this post just curious about your thoughts on barrel life. I had a previous 6gt barrel which I loaded with 4166 32.4gr 105's, consistent ES of around 10 (ten shot string) and SD of 3. Yes you are correct speed was only around 2800 but I also got 3200 rounds on that barrel. It was a hammer until then.
I think there is something to say for running a little slower to save barrel life, especially when you find a barrel that shoots and you want it to last.
my 2cents

 

[4O6shootist]

I'm not disagreeing with this post just curious about your thoughts on barrel life. I had a previous 6gt barrel which I loaded with 4166 32.4gr 105's, consistent ES of around 10 (ten shot string) and SD of 3. Yes you are correct speed was only around 2800 but I also got 3200 rounds on that barrel. It was a hammer until then.
I think there is something to say for running a little slower to save barrel life, especially when you find a barrel that shoots and you want it to last.
my 2cents

I don't fault anyone running mid or low nodes. I run 28" barrels generally and run the 2900-2930 node with 109s using H4350. My last two barrels have been pulled at 2500 and still shot well. The extra 2" has been worth 40-60fps from what I've observed depending on burn rate, it takes me a slight increase in pressure to get to the next node VS a guy with a 26" barrel. When I ran 4166 to break in with 109s 32.4gr was right around 2840fps prior to speed up.

 

[CK1.0]

2850-2900fps seems to be the right zone for barrel life and also for what hammers from what I’ve seen.

I’ve got a bunch of SW Precision Rifle to use up, but I’m probably going to try 4831SC in the GT at some point…

I figure hitting full case fill it’d be right around ~2850fps or so…

 

[todd]

I'm trying the heavy and slow approach this year. I went from 105's at 3010 (33.66g Varget) to 115 DTACs at 2725 (31.0g Varget) in 8X fired Hornady brass. JBM shows the DTACs at 2725 with the same wind drift as the 105's at 3010. Just a fun experiment.

 

[357Max]

38.6 N555 is full but not compressed. Gives 2940 with 109LRHT in a 26” cut rifled Rock Creek. No pressure, I stopped there cause it is the happy place for the 109’s

I have all the other typical powders, but it shoots so well with the 555 I have not needed to try anything else.

 

[CK1.0]

I'm trying the heavy and slow approach this year. I went from 105's at 3010 (33.66g Varget) to 115 DTACs at 2725 (31.0g Varget) in 8X fired Hornady brass. JBM shows the DTACs at 2725 with the same wind drift as the 105's at 3010. Just a fun experiment.

I’ve been shooting 115’s and/or 112’s for a couple years now in 6mm and prefer the heavier/slower thing for sure over the lighter/faster approach with 105’s.

IMO it’s the same thing out until ~750-800, and past that the heavier bullets with more BC seem to be better for me.

YMMV

 

[Professor Oblivion]

2850-2900fps seems to be the right zone for barrel life and also for what hammers from what I’ve seen.

I’ve got a bunch of SW Precision Rifle to use up, but I’m probably going to try 4831SC in the GT at some point…

I figure hitting full case fill it’d be right around ~2850fps or so…

I've done some testing with H4831SC. 39.5 did well with 115 RDFs in a 7.5 twist 26" Bartlein. 2875-ish, slightly crunchy, but no pressure signs.

More details here: https://www.snipershide.com/shooting/threads/6gt-current-loads-and-progress.6995239/post-10313879

 

[jonthomps]

Jumping in the GT pool. Varget, Alpha brass, 450's, 108 Bergers. Couple of questions:

- Starting load?
- This isn't the OCD brass. How worried should I be about this?

 

[MDof2]

32.5
Not very.

 

[prebancolt]

Anyone suggestions for the Berger 115 VLDs? Varget, new Alpha OCD, 450s.

I see very conflicting reports of jump (60-100) vs little jump. Any concensus on what this bullet likes?

 

[CK1.0]

Anyone suggestions for the Berger 115 VLDs? Varget, new Alpha OCD, 450s.

I see very conflicting reports of jump (60-100) vs little jump. Any concensus on what this bullet likes?

Generally, with VLDs the consensus seems to be either “jam them or jump them” meaning anywhere from jam to maybe 20 thou off, or something more like .040” off or more (sometimes way more). FWIW, I’ve never really had good luck with VLDs closer in.

For me, with a new bullet (especially a VLD) I like to try them out wherever having the neck within the meat of the bullet’s bearing surface ends up landing… which is usually in the ~50 to ~100 thou off neighborhood (base to ogive).

I find the longer I jump, the longer the barrel acts/stays the same, but if everything between say 50 and 100 thou off shoots, then I park it at 50 thou off and never have to really think about it again for the life of the barrel.

 

[prebancolt]

Should I be concerned with shortened barrel life if I find a load at jam - 20 vs something in the 50 - 100 range. OR are the hotter loads going to affect the barrel life much more than the short jumps? Or both? I'm guessing the hotter loads.

I've loaded a few 108 ELDs at 33.4gr of Varget, Alpha OCD, 450s with 60 jump that gave respectable groups, but my MPA barrel is still new, less than 50 rds and I'm getting used to the MPA BA Comp chassis when my Vudoo sits in an ACC. I like the ACC better.

 

[4O6shootist]

Should I be concerned with shortened barrel life if I find a load at jam - 20 vs something in the 50 - 100 range. OR are the hotter loads going to affect the barrel life much more than the short jumps? Or both? I'm guessing the hotter loads.

I've loaded a few 108 ELDs at 33.4gr of Varget, Alpha OCD, 450s with 60 jump that gave respectable groups, but my MPA barrel is still new, less than 50 rds and I'm getting used to the MPA BA Comp chassis when my Vudoo sits in an ACC. I like the ACC better.

Keeping velocity/psi down is more beneficial to barrel life than longer jumps. You're already jumping 60k, that's plenty of jump.

 

[CK1.0]

Should I be concerned with shortened barrel life if I find a load at jam - 20 vs something in the 50 - 100 range. OR are the hotter loads going to affect the barrel life much more than the short jumps? Or both? I'm guessing the hotter loads.

I've loaded a few 108 ELDs at 33.4gr of Varget, Alpha OCD, 450s with 60 jump that gave respectable groups, but my MPA barrel is still new, less than 50 rds and I'm getting used to the MPA BA Comp chassis when my Vudoo sits in an ACC. I like the ACC better.

From what I've seen, the longer the jump, and the lower the charge/slower speed, the longer the barrel life.

But in the end, go with what shoots, because barrels, like tires, don't last forever, YOLO lol!

Seriously, though, I'm still figuring things out a little for myself... there seem to be 2 ways to go about it: you can either find the longest jump the gun likes and then park it there and run it (I've had 2 6CM barrels that I've run 100 thou off like this and they both basically shot the same and consistent for their whole longer than usual lives), with a newer 6GT barrel, it shot great at 50 off all the way to 100 off, but due to the case and chamber being different/shorter than the 6CM barrels, I've been running it at 50 off and as the throat erodes it will back off and develop more jump "naturally".

That's why I mentioned the neck & bearing surface thing: using the exact same bullet, in 6CM, 100 off "looks better" meaning that the bullet isn't pushed back below where the shoulder starts, while in 6GT, somewhere ~60 thou off puts the bottom of the bullet below where the shoulder starts and 100 off would push the bullet a little too deep into the case for me... so I decided to leave the 6GT at 50 thou off. I haven't quite figured out if this neck/bearing surface relationship "is a thing" or just a coincidence yet, but it's been working out and I actually didn't notice it until after I'd already had the loads together (so I think it might be a thing lol).

The pic tells the story:

 

[4O6shootist]

@CK1.0 that's the reason I'm running a 0.170 freebore reamer. Most my bullets jump 40-80k, and this freebore works well with everything but the 115 dtac, it should have 0.200+ freebore

 

[CK1.0]

I’m not one of those guys who gets too deep in the weeds with reamers and chamber specs. I actually prefer SAAMI so I can always find the specs and remove any extra variables from the equation. YMMV.

But, yeah, different bullets “fit” differently depending on how long they are and depending on the case for sure.

I’d run my 6GT at 100 off too if the steeper/shorter shoulder allowed me to do it without having the ass end of my bullets below the shoulder.

 

[prebancolt]

I've seen split necks before, but this seemed unusual to me. Have you guys seen this before? It looks more like a blowout in the neck. Twice fired Hornady brass, did not anneal before pushing shoulder back 0.002" either time. Not sure of the exact load, but I used Varget to begin getting some velocity nubers with the 108 ELDs, and it never got past about 2950 max. Didn't notice it until I randomly picked this piece to see how my new AGS 3.0 annealer would cycle the brass through (no flame). While the case was spinning on the platform I spotted what looked like a mark from a marker that I was playing with. Upon closer inspection under a magnifying glass, this is what I saw. Haven't noticed this on any other pieces yet...

 

[MilSpecOkie]

I’ve seen some new brass that had marks in that shape in them. My buddy bought some brass and several were that way. Some split after a couple firings and some are still going. Personally I wouldn’t have shot them but he did. Maybe yours was that way from the factory and you never noticed it?

 

[Vandoogle13]

I had a couple hornady peices that had the same issue.
It was a manufacture flaw, I never loaded them.

 

[4O6shootist]

Shot some dtacs today, knew 35.5 gr was good charge weight from ladder shot a few weeks back. Seated them 20k jump and spun the tuner a bit. Started at setting 0, 2, 4. 300y groups at setting 4 and 5. Maybe sample size was too small, but the 10 shot zero validation at setting 4 looks damn good. Es was 13 on 10 shot zero. Velocity is 2860 from a 28" 7.5tw hawkhill barrel. Will be shooting at 800y e target tomorrow for validation and roughing in BC prior to Saturdays local prs match.

 

[AirgunnerPCP]

Has anyone had issues with Hornady brass having oversized primer pockets? On a fresh barrel, I loaded up 50rds of Hornady brass with 33gr of N150 (taken as a safe load based on other posters data) and 112 MB. I also loaded 50 with 107 SMKs. While shooting I had three pieces of brass with primers just fall out after the shot. Velocities were ~2750 and I didn't see any extrusion of the primer or much anything else that would scream pressure. Chucked it up to 3 bad pieces.

Loaded up another 50 virgin pieces at 33.5gr N150 and am having almost every other one primers fall out after the shot. Velocities are ~2850-2900 and again no other signs of pressure.

While seating primers the was a lower amount of force needed than I thought but it's hard to quantify that. Bad lot of brass? Thinking I should switch to Alpha and avoid this mess. Also I should note there's no damage to the bolt face and accuracy is excellent.

 

[MilSpecOkie]

@AirgunnerPCP what primers are you using? I notice in my Alpha brass that GMM primers don't have the same seating resistance as CCI primers. I haven't loaded any of the Hornady brass yet. I have 400 new pieces of Hornady GAP 6GT brass. Hopefully I don't have any issues.

 

[AirgunnerPCP]

@AirgunnerPCP what primers are you using? I notice in my Alpha brass that GMM primers don't have the same seating resistance as CCI primers. I haven't loaded any of the Hornady brass yet. I have 400 new pieces of Hornady GAP 6GT brass. Hopefully I don't have any issues.

Using CCI 450s. The same lot of primers had more resistance seating in multiple firings of FGMM 6.5CM brass.

 

[357Max]

@AirgunnerPCP what primers are you using? I notice in my Alpha brass that GMM primers don't have the same seating resistance as CCI primers. I haven't loaded any of the Hornady brass yet. I have 400 new pieces of Hornady GAP 6GT brass. Hopefully I don't have any issues.

I’ve been cycling through 400 pieces of Hornady that was originally loaded by Prime with 115RDF’s. 3rd firing & haven’t had to send any to the scrap bin.

My go to load has been 38.6 gr N555 with 109LRHT @2940 from 26” Primers have all been cci 41’s or BR-4. I can tell you the 41’s fit a little tighter than all others I’ve tried.

 

[MilSpecOkie]

Using CCI 450s. The same lot of primers had more resistance seating in multiple firings of FGMM 6.5CM brass.

I just got my 400 pieces of gap in the last couple weeks. I wonder if it's the same lot as yours?

 

[AirgunnerPCP]

I’ve been cycling through 400 pieces of Hornady that was originally loaded by Prime with 115RDF’s. 3rd firing & haven’t had to send any to the scrap bin.

My go to load has been 38.6 gr N555 with 109LRHT @2940 from 26” Primers have all been cci 41’s or BR-4. I can tell you the 41’s fit a little tighter than all others I’ve tried.

I've had good luck with Hornady brass in the past. Still have some 6.5CM with 5 or 6 firings. The 6GT brass had primer pockets that felt like brass that had been fired a few times upon initial loading.

 

[AirgunnerPCP]

I just got my 400 pieces of gap in the last couple weeks. I wonder if it's the same lot as yours?

Hard to tell. I bought mine a couple weeks ago from GAP and they just came in a bubble wrap bag. No markings.

 

[MilSpecOkie]

Hard to tell. I bought mine a couple weeks ago from GAP and they just came in a bubble wrap bag. No markings.

Mine too. My guess is they are from the same lot.

 

[AirgunnerPCP]

Mine too. My guess is they are from the same lot.

I'm still doing some digging. Maybe I loaded them way too hot? The data from my loads I gathered from other's experiences so who knows if the charge was pushing pressure. Signs point to no but it could be my fault entirely.

 

[021411]

Bought 400 pieces of brass from GAP at the beginning of April. No issues with CCI 450’s or Win #41 but I also haven’t gone past 2950 fps in my loads. I’ve hit pressure a few times and even those pieces of brass still have good pockets. I don’t prep the primer pocket other than scraping it out with a small pocket cleaner and using a q-tip to give it a quick wipe after. No reaming or uniforming. I hand prime..

 

[AirgunnerPCP]

Bought 400 pieces of brass from GAP at the beginning of April. No issues with CCI 450’s or Win #41 but I also haven’t gone past 2950 fps in my loads. I’ve hit pressure a few times and even those pieces of brass still have good pockets. I don’t prep the primer pocket other than scraping it out with a small pocket cleaner and using a q-tip to give it a quick wipe after. No reaming or uniforming. I hand prime..

Eh maybe my loads were just overpressure. I measured the pockets of some unfired brass and they seemed to be right at the min dimension (according to this site https://ballistictools.com/articles/primer-pocket-depth-and-diameter.php).

I don't prep primer pockets just load them up. I also hand prime and that's when they felt "off" to me. I've only loaded for 6.5CM using federal and hornady brass so I don't have much experience at all with the feel of things.

 

[MilSpecOkie]

It could be that, but the speeds don’t seem excessive with VV150?

 

[AirgunnerPCP]

It could be that, but the speeds don’t seem excessive with VV150?

They don't to me but I don't have the experience to make an exact call. So instead I think I'm going to change to alpha brass and start lower for initial firing.

 

[CK1.0]

I have 50pcs of Hornady 6GT brass I bought from GAP to supplement my Alpha stuff after I've lost pieces at matches (already lost 3-4) and was expecting them to not be as robust as the Alpha stuff, but I hope it's not total garbage. Primers falling out after the first firing is no bueno.

The Alpha OCD brass pockets are no joke on the first loading, pretty stout using a hand primer (which is good IMO). I'm hoping I can get 15+ firings out of them staying ~2850-2900fps (time will tell).

I'm on the third load cycle with 300pcs and the primer pockets felt like new Lapua stuff last time IIRC, so still very solid after 3x fired at 2853fps, CCI450, 34gn SWPR.

 

[jonthomps]

2023 GAP PPR. Random break-in load and seating depth. 2770fps w/ 41rds down the pipe. Cool little round.

 

[John Glidewell]

11 firings on my Alpha OCD brass and pockets are still like new. Running 2 rigs. RL 15.5 in both. CCI 400 and Fed 205M primers. 33.4 and 34 grains respectively for 109 Berger and 107 SMK both running 2950ish velocities. Almost 2k on both barrels now and still running strong. Hornady brass is shit. I have some and pockets go after 4 or 5 firings. I run QL and neither are near max pressure. Just dumped my 6.5 PRC Hornady brass too. Pockets went after 2 firings and that rig is no where near max. Been playing with N560 around 3k with 142 SMK. I have some ADG brass running same loads on 6+ firings and pockets are still fine. Can't even push a go gage in the pocket still. Pics are from 6GT. 34 of RL 15.5 at 2951 with 107 SMK @ .035 off lands. Steel was 714 yards, 4 shots.

 

[AirgunnerPCP]

Picked up some Alpha brass to test next. Plan is to start out 31.5gr N150 for first firing which I think is reasonable given the lower volume of the Alpha brass.

 

[Gray shooter]

11 firings on my Alpha OCD brass and pockets are still like new. Running 2 rigs. RL 15.5 in both. CCI 400 and Fed 205M primers. 33.4 and 34 grains respectively for 109 Berger and 107 SMK both running 2950ish velocities. Almost 2k on both barrels now and still running strong. Hornady brass is shit. I have some and pockets go after 4 or 5 firings. I run QL and neither are near max pressure. Just dumped my 6.5 PRC Hornady brass too. Pockets went after 2 firings and that rig is no where near max. Been playing with N560 around 3k with 142 SMK. I have some ADG brass running same loads on 6+ firings and pockets are still fine. Can't even push a go gage in the pocket still. Pics are from 6GT. 34 of RL 15.5 at 2951 with 107 SMK @ .035 off lands. Steel was 714 yards, 4 shots.View attachment 8140849View attachment 8140850View attachment 8140851

John, good write up. What length barrels are you running?

 

[John Glidewell]

John, good write up. What length barrels are you running?

28" blanks fished at 27".

 

[4O6shootist]

Picked up some Alpha brass to test next. Plan is to start out 31.5gr N150 for first firing which I think is reasonable given the lower volume of the Alpha brass.

I run 32.8gr in one barrel at 2910 with a 107smk, shoots half moa at distance.

 

[drglock]

11 firings on my Alpha OCD brass and pockets are still like new. Running 2 rigs. RL 15.5 in both. CCI 400 and Fed 205M primers. 33.4 and 34 grains respectively for 109 Berger and 107 SMK both running 2950ish velocities. Almost 2k on both barrels now and still running strong. Hornady brass is shit. I have some and pockets go after 4 or 5 firings. I run QL and neither are near max pressure. Just dumped my 6.5 PRC Hornady brass too. Pockets went after 2 firings and that rig is no where near max. Been playing with N560 around 3k with 142 SMK. I have some ADG brass running same loads on 6+ firings and pockets are still fine. Can't even push a go gage in the pocket still. Pics are from 6GT. 34 of RL 15.5 at 2951 with 107 SMK @ .035 off lands. Steel was 714 yards, 4 shots.View attachment 8140849View attachment 8140850View attachment 8140851

That Reloader 15.5 is the cats meow for the GT. I’m running 33.3grs with 109 ELDM’s at 2856.

 

[Hickswr]

That Reloader 15.5 is the cats meow for the GT. I’m running 33.3grs with 109 ELDM’s at 2856.

How’s temp stability compared to H4350 and Varget?

 

[drglock]

How’s temp stability compared to H4350 and Varget?

Just as good maybe better but I’ve only shot from low 40’s to low 90’s in matches so far. When I’ve chrono’d in those temps my five shot average has been 2849-2856. Only downside I’ve noticed with it is that it’s a bit dirtier than the other 2.

 

[AirgunnerPCP]

Picked up some Alpha brass to test next. Plan is to start out 31.5gr N150 for first firing which I think is reasonable given the lower volume of the Alpha brass.

Update: Fired about 30 rounds of the above and no primers falling out. Velocity was 2769 average with still good SDs and accuracy. Reprimed a piece of the fired Alpha brass and primer pockets still very tight.

 

[4O6shootist]

Update: Fired about 30 rounds of the above and no primers falling out. Velocity was 2769 average with still good SDs and accuracy. Reprimed a piece of the fired Alpha brass and primer pockets still very tight.

That's def on the low psi side. Lot of room to add powder. My brass is on 6 firings with 109s at 2920. Primers still tighter than 1-2x fired lapua.

 

[AirgunnerPCP]

That's def on the low psi side. Lot of room to add powder. My brass is on 6 firings with 109s at 2920. Primers still tighter than 1-2x fired lapua.

Yep, once I get past the initial firings I'll bump up in charge weight.