Range Report  6GT Project/Range Report

Darkside-Six

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  • Oct 8, 2013
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    I have to admit, I'm starting to get pretty frustrated with the GT. Between two barrels, one an Impact pre-fit and one a Bartlein chambered using their JGS reamer, I can't get anywhere close to the velocities people are claiming with 109s. Virgin Alpha, doesn't matter. Virgin Hornady, doesn't matter. Once fired Hornady? Nope. Once I start getting up past 2900 with 4350 or Varget, I get heavy bolt lift and other pressure signs. Might as well just run a BR.

    that’s odd. Is the pre-fit from Impact themselves? I’m on my 2nd impact Pre-fit from Area 419. 1st one had about 350 rounds on it but had a groove in the chamber so I had to send it back. 2nd one has about 750ish now. 34.5 varget with Hornady brass and CCI 450’s have been the sweet spot for multiple bullets, both by myself and a few others I shoot with. 2950 with 109’s.

    I will note that around 500 rounds I had a nasty carbon ring that started having pressure issues and 2 others I know had similar thing around the same round count area. Once I scrubbed that out it went back to normal.
    2900 isn’t that bad honestly and will probably improve barrel life.
     

    RoterJager

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    that’s odd. Is the pre-fit from Impact themselves? I’m on my 2nd impact Pre-fit from Area 419. 1st one had about 350 rounds on it but had a groove in the chamber so I had to send it back. 2nd one has about 750ish now. 34.5 varget with Hornady brass and CCI 450’s have been the sweet spot for multiple bullets, both by myself and a few others I shoot with. 2950 with 109’s.

    I will note that around 500 rounds I had a nasty carbon ring that started having pressure issues and 2 others I know had similar thing around the same round count area. Once I scrubbed that out it went back to normal.
    2900 isn’t that bad honestly and will probably improve barrel life.

    Yeah the one with 1000 on it is direct from Impact. The other is direct from bartlein though its not a profit.

    I found a pretty decent node at 2860ish with H4350 and I don't mind running slow. Just disappointing when it's been advertised as a 2900-3000+ caliber.
     
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    Darkside-Six

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    Yeah the one with 1000 on it is direct from Impact. The other is direct from bartlein though its not a profit.

    I found a pretty decent node at 2860ish with H4350 and I don't mind running slow. Just disappointing when it's been advertised as a 2900-3000+ caliber.
    Yeah that’s strange. Most of the people I see shooting it are around 2950ish with 109 and 110’s and 3000-3050 with 105’s. That’s with varget anyways. I found some decent nodes with RL16 and were a little faster but varget has just been accurate as hell with very low spreads.
     

    Professor Oblivion

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    Just started with a 6GT. All my previous 6mm's were .243s.

    26" 7.5 twist Bartlein 5R HV
    Tikka factory action and trigger
    AICS 10 round steel mags (all fed smoothly)
    KRG X-Ray chassis
    Burris XTR II 8-40X-50
    Vortex matched rings
    EGW base
    Area 419 Hellfire brake (not used for this testing)

    Virgin Hornady brass 'mandrel sized' using just the expander stem in a Lee .243 Win. collet die (yes, I'm that cheap), and seating done with a Whidden micrometer die (but not *that* cheap :). I was pleasantly surprised by the Hornady brass. All 100 pieces were within 1.5 grains of each other (136 grain avg.), the untrimmed cases were 1.718 ±.002, and unsized headspacing was 1.353 ±.0005 (1x fired cases are showing 1.354 ±.0005 headspace and still ~1.718 trim length).

    Used light (33.0 and 32.0 grains) of N140--fairly clean burning and close to Varget--behind some leftover 90 grain Nosler BTs and 95 grain Hornady SSTs for barrel break-in and rough 100-200 yard sight-in. Then used 37.0 and 37.5 of H4350 and 35.0, 35.5, and 36.0 grains of VV N150 behind 105 RDFs for 200 yard testing. All loads used CCI 450 primers.

    I couldn't find any data on N150 for the GT, but knew it is closer to H4350 than it is to N140 and Varget in terms of burn rate. Still, even 35.0 is a bit too hot. No ejector marks, even at 36.0, but slightly stiff bolt lift on all and some light burnishing on the headstamps of a few. Flattened, but not cratered, primers. I have since done a face palm and looked at the VV N150 data for 6 Creedmoor, which tops out at 34.9 for the Hybrid Target and 35.8 for the VLD Target. D'OH! That's why it is called a *relative* burn rate chart.

    Initial COAL/CBTO was determined by decreasing the seating on an empty case until I could gently, VERY gently, close the bolt, then seating ~.025 more (tested and inspected all loaded rounds to ensure no marking on the bullets). This worked out to:

    2.450/1.962 Nosler 90 BT
    2.405/1.930 Hornady 95 SST
    2.540/1.960 Nosler 105 RDF

    The target image is 200 yard testing of the H4350 and N150 loads (slight 3-5 mph head wind, ~90 degrees F, 80% relative humidity, near sea level, using a bipod and rear bag on a bench). Odd, but not unexpected, flyers with H4350 (due to the rough sizing/seating, not the powder, I'm sure), but okay results. N150 did a little better, but still a lot of room for improvement for both.

    All should improve with 1x fired and properly sized cases, and some chronographing. If so, great. If not, then will be testing with N140, Varget, and Reloder-16. I have now drilled and tapped a fired case for my OAL gauge, and look forward to some proper seating depth testing. I also have a Whidden FL bushing sizing die and can test neck tension if needed, but I'm doing plenty of "foolish wand waving and silly incantations" to avoid having to turn case necks :). I'd like to stick with the 105 RDFs if I can since they shoot great in my .243s and I have a LOT of them, but I also have some 108 ELD-Ms and some 115 RDFs. Will update ASAP.
     

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    kindabitey

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    Thanks for the N150 info. I've been waiting for someone to post up some results with that.
     

    SouthFLShootin

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    I have a GT that has about 1100 rounds on it with a 26" Proof 1/7.5 twist barrel. I run into pressure in the mid 2900's with both H4350 and Varget. I found a nice node just above 2900 and have been running it there for the time being. It hammers jumping the 109 .065, but I also feel like I should be getting more velocity before pressure.

    I am having a bartlien 4 groove spun up shortly and will be interested to see what that barrel does. Both will be done with the same reamer and Smith.

    I just measured throat errosion and I am at .018" after 1100 rounds with some PRS style shooting.
     

    Darkside-Six

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    @Darkside-Six the weird thing is that there are four of us regulars in my local club that are shooting GT and all of us are having issues getting it anywhere close to 3k without pressure.

    what is your seating depth? I know with the hybrids they are not very jump sensitive but sometimes seating them a little deeper will eliminate that
     

    MakeSawdust

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    I have a GT that has about 1100 rounds on it with a 26" Proof 1/7.5 twist barrel. I run into pressure in the mid 2900's with both H4350 and Varget. I found a nice node just above 2900 and have been running it there for the time being. It hammers jumping the 109 .065, but I also feel like I should be getting more velocity before pressure.

    I am having a bartlien 4 groove spun up shortly and will be interested to see what that barrel does. Both will be done with the same reamer and Smith.

    I just measured throat errosion and I am at .018" after 1100 rounds with some PRS style shooting.
    You are focusing on the wrong thing. The gun hammers. Forget what the velocity is. It doesn't matter. None of the guys that are winning at prs consistently are running fast. Most are running very mild and CONSISTENT loads. There is very little reason to focus on the velocity. I will give you an example. My wife shoots a 6 Dasher at 2890 fps with a 105 Hornady HPBT. She is not a very serious competitor, but the gun is a hammer and will hold a waterline at 800 yds that is under an inch. It is uncanny. The wind hold for her load in a 10 mph wind at 1000 yds is 2.2 mils.

    I shoot a 243ai with 115 DTACS at 3000 fps (also mild) because I see too many ro's not calling hits with the small 6mm calibers. My "hotrod windcheater" has a 1000 yd 10 mph wind hold of 1.6 mils in the same conditions. The difference looks to be significant, until you examine it through another lense.

    A one mph wind error will make the 6 dasher miss by .22 mils and the 243ai misses by .16 mils for a difference of .06 mils between them. The difference is 2.16" at 1000 yds. Both shots stay inside of a 2 moa target. Extend the error to 2 mph and both miss a 2 moa target.

    The next part is what most people miss. I struggle to get my gun and load to hold 3-4 in of vertical at the same 800 yd target. With the Dasher it is automatic. Just about any reasonable load is at or under 2" of vertical at 800 yds. There is much less vertical uncertainty which makes every circle and diamond target wider.

    The differences are even smaller when choosing between the high node and the low node for a particular cartridge. The example above was extreme in that the faster velocity was also with a bullet that has a g1 bc that is 17% higher than the bullet being utilized in the slower cartidge.

    Running the low node will extend barrel life and eliminate problems in rainy or dirty conditions that arise from pressure. Brass will also last longer.

    The only time it makes sense to push a cartidge is in elr applications or when there is range uncertainty. Neither of those exist in a typical prs match that the 6 gt was designed for.

    After thinking about it in this manner I am convinced there is little need for large hotrod cartridges or chasing speed for prs shooting. This is especially true if hit indicators are used on targets. It makes more sense to shoot a cartridge with good accuracy potential that is easy to load for and has decent barrel life. Running the low node will help far more by being less finicky, extending brass life, and preventing issues from pressure in rain. Running the high node chasing velocity makes one vulnerable to all of these potential issues.

    Just my $0.02 worth when it comes to chasing velocity.
     

    Dthomas3523

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    You are focusing on the wrong thing. The gun hammers. Forget what the velocity is. It doesn't matter. None of the guys that are winning at prs consistently are running fast. Most are running very mild and CONSISTENT loads. There is very little reason to focus on the velocity. I will give you an example. My wife shoots a 6 Dasher at 2890 fps with a 105 Hornady HPBT. She is not a very serious competitor, but the gun is a hammer and will hold a waterline at 800 yds that is under an inch. It is uncanny. The wind hold for her load in a 10 mph wind at 1000 yds is 2.2 mils.

    I shoot a 243ai with 115 DTACS at 3000 fps (also mild) because I see too many ro's not calling hits with the small 6mm calibers. My "hotrod windcheater" has a 1000 yd 10 mph wind hold of 1.6 mils in the same conditions. The difference looks to be significant, until you examine it through another lense.

    A one mph wind error will make the 6 dasher miss by .22 mils and the 243ai misses by .16 mils for a difference of .06 mils between them. The difference is 2.16" at 1000 yds. Both shots stay inside of a 2 moa target. Extend the error to 2 mph and both miss a 2 moa target.

    The next part is what most people miss. I struggle to get my gun and load to hold 3-4 in of vertical at the same 800 yd target. With the Dasher it is automatic. Just about any reasonable load is at or under 2" of vertical at 800 yds. There is much less vertical uncertainty which makes every circle and diamond target wider.

    The differences are even smaller when choosing between the high node and the low node for a particular cartridge. The example above was extreme in that the faster velocity was also with a bullet that has a g1 bc that is 17% higher than the bullet being utilized in the slower cartidge.

    Running the low node will extend barrel life and eliminate problems in rainy or dirty conditions that arise from pressure. Brass will also last longer.

    The only time it makes sense to push a cartidge is in elr applications or when there is range uncertainty. Neither of those exist in a typical prs match that the 6 gt was designed for.

    After thinking about it in this manner I am convinced there is little need for large hotrod cartridges or chasing speed for prs shooting. This is especially true if hit indicators are used on targets. It makes more sense to shoot a cartridge with good accuracy potential that is easy to load for and has decent barrel life. Running the low node will help far more by being less finicky, extending brass life, and preventing issues from pressure in rain. Running the high node chasing velocity makes one vulnerable to all of these potential issues.

    Just my $0.02 worth when it comes to chasing velocity.

    I think it’s more of a principle thing. Cartridge was advertised to get to X speed and is only getting Y speed.

    Seems to be a fairly common complaint. The reason could be operator error, but if so, there’s a lot of operator error happening as there a lot of people reporting similar issues.
     

    reubenski

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    what is your seating depth? I know with the hybrids they are not very jump sensitive but sometimes seating them a little deeper will eliminate that
    I have found Hybrids to be more jump sensitive than 107 SMKs or DTACs. It's all in the shape of the nose. That was the entire concept of the Hybrid. Combine a higher BC VLD nose shape with a more tolerant traditional nose shape, aka...a Hybrid. But I have found in practice that while it is an improvement over a VLD it still can't compete, in terms of jump tolerance, with traditional nose shapes. Just compare 108 BT's, 107 SMK's, DTACs, 105HPBT's with the Hybrids and then with the older RDF's, the newer 110/ 183/ and 95 SMKs. A scale of easily tune'able to jump sensitive and then picky to the point some people just don't shoot them.
     

    SouthFLShootin

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    You are focusing on the wrong thing. The gun hammers. Forget what the velocity is. It doesn't matter. None of the guys that are winning at prs consistently are running fast. Most are running very mild and CONSISTENT loads. There is very little reason to focus on the velocity. I will give you an example. My wife shoots a 6 Dasher at 2890 fps with a 105 Hornady HPBT. She is not a very serious competitor, but the gun is a hammer and will hold a waterline at 800 yds that is under an inch. It is uncanny. The wind hold for her load in a 10 mph wind at 1000 yds is 2.2 mils.

    I shoot a 243ai with 115 DTACS at 3000 fps (also mild) because I see too many ro's not calling hits with the small 6mm calibers. My "hotrod windcheater" has a 1000 yd 10 mph wind hold of 1.6 mils in the same conditions. The difference looks to be significant, until you examine it through another lense.

    A one mph wind error will make the 6 dasher miss by .22 mils and the 243ai misses by .16 mils for a difference of .06 mils between them. The difference is 2.16" at 1000 yds. Both shots stay inside of a 2 moa target. Extend the error to 2 mph and both miss a 2 moa target.

    The next part is what most people miss. I struggle to get my gun and load to hold 3-4 in of vertical at the same 800 yd target. With the Dasher it is automatic. Just about any reasonable load is at or under 2" of vertical at 800 yds. There is much less vertical uncertainty which makes every circle and diamond target wider.

    The differences are even smaller when choosing between the high node and the low node for a particular cartridge. The example above was extreme in that the faster velocity was also with a bullet that has a g1 bc that is 17% higher than the bullet being utilized in the slower cartidge.

    Running the low node will extend barrel life and eliminate problems in rainy or dirty conditions that arise from pressure. Brass will also last longer.

    The only time it makes sense to push a cartidge is in elr applications or when there is range uncertainty. Neither of those exist in a typical prs match that the 6 gt was designed for.

    After thinking about it in this manner I am convinced there is little need for large hotrod cartridges or chasing speed for prs shooting. This is especially true if hit indicators are used on targets. It makes more sense to shoot a cartridge with good accuracy potential that is easy to load for and has decent barrel life. Running the low node will help far more by being less finicky, extending brass life, and preventing issues from pressure in rain. Running the high node chasing velocity makes one vulnerable to all of these potential issues.

    Just my $0.02 worth when it comes to chasing velocity.
    I would have to agree with everything you said 100%, thats why I'm not too upset about not achieving the higher velocity. In all reality, 75-100fps is really not doing anything for me. On the other hand, the cartridge was marketed as being 3000+fps capable, and I am finding quite a few people have trouble getting there. I am also at almost 0 elevation and its been 90 degrees out, so I'm sure that has an effect on pressure.

    I just did a seating depth test today after erroding the throat .018 before changing seating depth, and now the gun seems to like.the .030-.040 jump. Regardless, im not going to complain about the performance right now, was just makimg observations.
     
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    What magazines, and feed lip dimensions are you all finding work best with the GT and and Impact.
     

    MakeSawdust

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    I think it’s more of a principle thing. Cartridge was advertised to get to X speed and is only getting Y speed.

    Seems to be a fairly common complaint. The reason could be operator error, but if so, there’s a lot of operator error happening as there a lot of people reporting similar issues.
    I certainly understand that sentiment. I think just about every cartridge is promoted excessively and touted as the next game changer right after they are created and released. Once you've messed with a few of them it starts to become obvious that there are no free lunches and every cartridge is a tradeoff of sorts. There are a lot of variables even with the same cartridge. People that have different use cases for the same cartridge often report wildly different results.

    I think the 6 gt is a fine cartridge, but I don't see it as anything groundbreaking. They (basically) took a 6 Dasher and lengthened it to make it feed from magazines more reliably. I'm not surprised to see that the velocity is similar to the Dasher, regardless of what was touted by the promoters.

    Even given the above, I understand the frustration when things are over promised and under delivered.
     
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    kindabitey

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    What magazines, and feed lip dimensions are you all finding work best with the GT and and Impact.
    I'm running ARC w/LRI followers, MDT 12 rd, Alpha and AI without any problems. I had to cleanup the edges of the ARC mag feed lips with some sandpaper.
     
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    reubenski

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    I'm getting 2950 - 3020, depending on the load, pretty easily. There is something strange going on with a certain amount of folks that are barely breaking 2900, or not. I truthfully think Varget is a bit too fast but even then some folks are struggling with velocity. It seams like 70% of GT shooters are doing 2950 - 3000 and 30% can't or can barely get 2900. It is a little weird.
     
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    I'm running ARC w/LRI followers, MDT 12 rd, Alpha and AI without any problems. I had to cleanup the edges of the ARC mag feed lips with some sandpaper.
    Thank you. I have a selection of magazines MDT 12, AICS, Magpul AICS... etc. I've read that it is finicky. Would you mind measuring the front rear and middle of your feed lips on the MDT 12's?
     

    kindabitey

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    Thank you. I have a selection of magazines MDT 12, AICS, Magpul AICS... etc. I've read that it is finicky. Would you mind measuring the front rear and middle of your feed lips on the MDT 12's?
    What ever they were from the factory. I haven't touched them. Some of it has to do with mag height in the stock/chassis. The newer MPA have an adjustable mag height.
     
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    xocyrusx

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    Hello all... I actually had some feeding issues this weekend with my GT and a bit confused running a poly mdt 10 rnd in a bighorn origin. It was good for the first couple of rounds then would t pick up the next. A smack to the bottom and it would catch. Any suggestions?
     

    reubenski

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    Hello all... I actually had some feeding issues this weekend with my GT and a bit confused running a poly mdt 10 rnd in a bighorn origin. It was good for the first couple of rounds then would t pick up the next. A smack to the bottom and it would catch. Any suggestions?
    Did you check that the follower was pushing the round all the way up agin the feed lips? Spring tension? Friction on the follower sliding in the mag?

    Try a 10rd metal AICS mag. Not a MDT branded mag though.
     
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    xocyrusx

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    Did you check that the follower was pushing the round all the way up agin the feed lips? Spring tension? Friction on the follower sliding in the mag?

    Try a 10rd metal AICS mag. Not a MDT branded mag though.
    That’s what I was thinking was good and tested after your post. Tension and push to the feed lips looks good but on a 10 round mag after cycling the bolt 7 rounds I would get a failure to feed. Did that about 10 times and it was pretty consistent on the 7-8th round it would fail.

    I’ll try a metal mag and see. Any suggestions? 12 rounders?
     

    SouthFLShootin

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    I run the MDT poly mags with the metal feed lips and I have had zero issues in an MDT ACC chassis and Curtis vector action. They are only 10 rounders though. It looks like you could put an extension on it if you wanted to, but I haven't even looked into it. I actually prefer them without an extension just because I don't like the extra length in the magazine and have never had an issue sled loading or just swapping mags on a position change.
     
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    xocyrusx

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    I run the MDT poly mags with the metal feed lips and I have had zero issues in an MDT ACC chassis and Curtis vector action. They are only 10 rounders though. It looks like you could put an extension on it if you wanted to, but I haven't even looked into it. I actually prefer them without an extension just because I don't like the extra length in the magazine and have never had an issue sled loading or just swapping mags on a position change.

    That’s what I was thinking as it’s a pressure / tension Issue. Either a spring issue or the feed lips. The mag I’m using now is the poly feed lips so I need to try metal.
     

    kthomas

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    I think it’s more of a principle thing. Cartridge was advertised to get to X speed and is only getting Y speed.

    Seems to be a fairly common complaint. The reason could be operator error, but if so, there’s a lot of operator error happening as there a lot of people reporting similar issues.

    While I applaud and respect George for all he's done for the gun community, and his inventiveness for coming up with new cartridges to benefit our segment of the community, he does have a little bit of a habit of overselling the cartridges he brings to life.

    I'm not sure if that's over optimism or a bit of a sales pitch on his part, but those that look at the history of his cartridges should expect to be a bit more conservative on all figures from what he advertises.
     

    RoterJager

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    While I applaud and respect George for all he's done for the gun community, and his inventiveness for coming up with new cartridges to benefit our segment of the community, he does have a little bit of a habit of overselling the cartridges he brings to life.

    I'm not sure if that's over optimism or a bit of a sales pitch on his part, but those that look at the history of his cartridges should expect to be a bit more conservative on all figures from what he advertises.

    I agree

    I'm starting to think that 2800-2900 is all im going ro get out of the cartridge running A-tips and 4350. Im fine with that as long as I get decent barrel life.
     

    RoterJager

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    @reubenski

    Hornady Virgin brass
    36.5 of H4350 (2820)
    37.0 of H4350 (2850)
    Hornady 110 A tips at 0.050" off
    CCI450 primers
    Neck tension set with a K&M 0.004" mandrel.

    I might try to go back to 0.030" off the lands before the next two day match but we'll see
     
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    reubenski

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    @reubenski

    Hornady Virgin brass
    36.5 of H4350 (2820)
    37.0 of H4350 (2850)
    Hornady 110 A tips at 0.050" off
    CCI450 primers

    I might try to go back to 0.030" off the lands before the next two day match but we'll see
    This slow velocity/ early pressure thing is blowing my mind. It seams to happen to folks kinda indiscriminately. I can run up to 38.3gr of 4350 before I even start to see pressure. I'm doing 2960 with 37.6gr of 4350 and 110 SMKs in a 24" barrel.
     
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    SouthFLShootin

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    This slow velocity/ early pressure thing is blowing my mind. It seams to happen to folks kinda indiscriminately. I can run up to 38.3gr of 4350 before I even start to see pressure. I'm doing 2960 with 37.6gr of 4350 and 110 SMKs in a 24" barrel.
    Whats your altitude? Temps?
     
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    RoterJager

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    This is a pic of the chamber with the first 30rds fired after a chamber cleaning. I don't see any major carbon issues and I'm pretty diligent on cleaning the carbon out of my chambers to avoid getting a carbon ring. Especially after a bad experience I had with a Creedmoor.
    carbon ring.jpg

    This is a pic of the rifling after 650 rounds on the barrel.
    throat erosion.jpg
     

    SouthFLShootin

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    I don't have the reloading software or first hand knowledge to prove it , but I bet that has something to do with you higher velocities. In FL I may be 20-30 ft above sea level on a good day. I can still get 109s to 2950 on a 26" proof, but that's about max.
     

    reubenski

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    I don't have the reloading software or first hand knowledge to prove it , but I bet that has something to do with you higher velocities. In FL I may be 20-30 ft above sea level on a good day. I can still get 109s to 2950 on a 26" proof, but that's about max.
    I've already tried to equate DA to MV fluctuations. Doesn't pan out. If anything it would be a moisture content in powder issue
     

    reubenski

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    This is a pic of the chamber with the first 30rds fired after a chamber cleaning. I don't see any major carbon issues and I'm pretty diligent on cleaning the carbon out of my chambers to avoid getting a carbon ring. Especially after a bad experience I had with a Creedmoor.
    View attachment 7373692

    This is a pic of the rifling after 650 rounds on the barrel.
    View attachment 7373693
    A lot of folks definitely get a lot faster than what you're getting. My hunch was the thicker Alpha brass but that doesn't sound like it.
     

    SouthFLShootin

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    I've already tried to equate DA to MV fluctuations. Doesn't pan out. If anything it would be a moisture content in powder issue
    Interesting. The correlation in moisture content and powder being what? The humidity is very high here, but the powder is kept indoors where the AC regulates the RH to about 45-50% @ 74* at all times.
     

    reubenski

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    Higher the moisture content, slower the mv is and quicker you get higher pressure. The more dry, faster velocity and a larger charge without the pressure.

    I'm in Colorado
     

    Darkside-Six

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    There's four of us in the area that shoot the GT, only one is getting up above 2950 without issues.
    see thats what is crazy cause you're in WI, correct? im in MI and there are 5-6 of us that shoot with no issues and faster speeds. i think all of us over here have the first lot of hornady brass. 34.5 varget with A-tips gave me 2960. i'll have to go back and look at what the RL16 load i found was but it was running right at 3000 with no pressure issues. i stuck with varget cause it seemed to be more consistent.
     

    RoterJager

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    see thats what is crazy cause you're in WI, correct? im in MI and there are 5-6 of us that shoot with no issues and faster speeds. i think all of us over here have the first lot of hornady brass. 34.5 varget with A-tips gave me 2960. i'll have to go back and look at what the RL16 load i found was but it was running right at 3000 with no pressure issues. i stuck with varget cause it seemed to be more consistent.

    Im in WI. I can get 2920 out A tips and 34.4 of Varget but I start getting heavy bolt lift and ejector swipe, especially if its warm out. It's enough that I dont want do a water test on it.
     

    Dthomas3523

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    This slow velocity/ early pressure thing is blowing my mind. It seams to happen to folks kinda indiscriminately. I can run up to 38.3gr of 4350 before I even start to see pressure. I'm doing 2960 with 37.6gr of 4350 and 110 SMKs in a 24" barrel.

    This is why I decided to go back to dasher. I couldn’t figure out what caused the indiscrimination. When I ran initial tests on alpha brass I had, I went to 36.0 without issue. Then not long after, on three barrels (clean), I had issues all the way down to 31.7 grains of varget.

    This combined with many other I trust having similar issues (even with hornady brass at times), I couldn’t figure out what the common denominator was as it was all over the place. And, some guys are having really good luck with alpha and hornady.

    So, I went back to a cartridge you don’t hear a lot of wild stuff happening randomly.
     

    reubenski

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    This is why I decided to go back to dasher. I couldn’t figure out what caused the indiscrimination. When I ran initial tests on alpha brass I had, I went to 36.0 without issue. Then not long after, on three barrels (clean), I had issues all the way down to 31.7 grains of varget.

    This combined with many other I trust having similar issues (even with hornady brass at times), I couldn’t figure out what the common denominator was as it was all over the place. And, some guys are having really good luck with alpha and hornady.

    So, I went back to a cartridge you don’t hear a lot of wild stuff happening randomly.
    You had the same high pressure issue repeat on 3 barrels in a row?
     
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    Dthomas3523

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    You had the same high pressure issue repeat on 3 barrels in a row?

    Yep. A proof stainless and two bartleins.

    Ai, Lone Peak, and Terminus actions.

    All had heavy bolt lift with virgin and fired brass. New and post 200 round count on barrels.
     

    Darkside-Six

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    Yep. A proof stainless and two bartleins.

    Ai, Lone Peak, and Terminus actions.

    All had heavy bolt lift with virgin and fired brass. New and post 200 round count on barrels.
    Didn’t Alpha come out and try to make a bunch of excuses about it though?? 🤦‍♂️🤦‍♂️🤦‍♂️
     

    reubenski

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    Yep. A proof stainless and two bartleins.

    Ai, Lone Peak, and Terminus actions.

    All had heavy bolt lift with virgin and fired brass. New and post 200 round count on barrels.
    That's pretty wild. If I had that experience, three times in a row I'd be pretty convinced that the 6gt can't run 2950 plus and I'd be scratching my head about folks are advertising more than that. And what's more confounding is that its not like there's a ton of different reamers floating around. I imagine most everyone is using the same reamer spec.

    I truly believe the idea that a thicker case gets the same velocity with less powder is, most of the time, erroneous. I do believe that a thicker case will get the same pressure with less powder. Ive just never got the same velocity to go along with it. So, normally, I'd assume it's the thick alpha brass but I was getting 3020 with a 105 and H4350. As well in Hornady brass.

    A couple of months ago I was looking at a GT case and a Dasher case in my hand and I came to the conclusion that the GT has just about the perfect case dimensions. But as I've shot my GT barrel it just doesn't impress over a Dasher. I have as a result never shot my GT in Competition and my Dasher remains my go to, with a BR on local club back up duty.
     

    Dthomas3523

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    That's pretty wild. If I had that experience, three times in a row I'd be pretty convinced that the 6gt can't run 2950 plus and I'd be scratching my head about folks are advertising more than that. And what's more confounding is that its not like there's a ton of different reamers floating around. I imagine most everyone is using the same reamer spec.

    I truly believe the idea that a thicker case gets the same velocity with less powder is, most of the time, erroneous. I do believe that a thicker case will get the same pressure with less powder. Ive just never got the same velocity to go along with it. So, normally, I'd assume it's the thick alpha brass but I was getting 3020 with a 105 and H4350. As well in Hornady brass.

    A couple of months ago I was looking at a GT case and a Dasher case in my hand and I came to the conclusion that the GT has just about the perfect case dimensions. But as I've shot my GT barrel it just doesn't impress over a Dasher. I have as a result never shot my GT in Competition and my Dasher remains my go to, with a BR on local club back up duty.

    I know some are having good luck with gt. And I trust their numbers in the 3050 range. But I didn’t experience the same thing and couldn’t find exactly why not. And I haven’t had any similar negative experiences with any other round I load for except dasher using alpha.
     
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    SouthFLShootin

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    I had my proof barrel fall out of a node around the 1200 round mark and start shooting poorly. Played with seating depth without any luck. Ended up droping the charge by .8 grains and found another node at a lower velocity. I shoot it around 2890-2900 with SDs below 6 generally.

    I just shot a match with it and did pretty well with zero dope data on it. Made contact out to 1300 yards and placed in the top ten. I have one more match this month that I'm going to shoot with this barrel then Im going to switch over to a Bartlien 4 groove. If the Bartlien is as hard to tune and doesn't get the intended velocoties, I will be ditching the caliber and likely switching over to a dasher or BR for the ease of use.