6GT powder ladder. Input desired (seating ladder added 9/15 & 9/21)

[jxb]

Here, I'm talking about glance at this ladder and give me your thoughts, don't worry about offending me, I have very thick skin.

Those that read groups and don't mind sharing your input, it would be welcome. I'm new to this so lots of learning needed. Being a new rig I started low expecting to stay below pressure. I have never experienced all my groups in the ladder so small and with so little variation in position. Based on this output I'm thinking not only will I shift the loads to the right to get more fps and maybe find some indication of pressure, but also do it at 200 or 300 yards so I can better see the patterns. I'll also switch to front rest and tracking rear bag to try to remove me from the equation as much as possible. This other range I'll have possible wind, but concrete benches and solid target backers so I'm thinking that's the way to go. SD/ES are all good, but I purposely didn't include them, I'm looking for input on the groups and relation to each other initially.

6GT, 28", Alpha(new+prep), Bart's 105Hammer (0.012off touch), cci450, bipod and squeeze bag.
100yrds in pit, no wind but shared wood bench and no solid target backing
first 40 rounds through new barrel
different target 6 rnds, get on paper and fouling.
Attached target top row is sighters (with turret changes), then 30 shot ladder test 3 shots per, 10 deep (no turret changes)

Ladder groups shot left to right 1-5, then 6-10 next row (2" circles, 1/2" centers)
0.3 incr. 31.2gr--33.9gr Varget
2771.3--2970.1 average fps (min/max)
no indication of pressure in brass and primers, and no clickers.
The plan was to do powder ladder first, then seating.

 

[Tangent]

To be honest I don't see a lot in it. I'd be interested to see ten shots at the load with the smallest group versus the largest.

 

[jxb]

That was my thinking when I looked at it. I'm thinking there's a node around 34-35gn based on my other 6GT and shooting it at 200 will show better pattern. I also left thinking, too much shooter error in this to know much. I might also try H-4350 as I should get better case fill.

 

[dthomas]

If you can go higher I would but I don't know what normal charges are for that cartridge. For the groups you have I would test between groups 7-9.

 

[rijndael]

If you can go higher I would but I don't know what normal charges are for that cartridge. For the groups you have I would test between groups 7-9.

2970 for a 105 is pretty close to top end of velocity for a 6GT.

 

[drop_point]

I'd repeat the whole bottom row and see if its repeatable. If it is, 7-8-9 may be a good starting point.

 

[jxb]

If you can go higher I would but I don't know what normal charges are for that cartridge. For the groups you have I would test between groups 7-9.

yeah I was wondering if 7-9 was a node, prints same location.

2970 for a 105 is pretty close to top end of velocity for a 6GT.

I was thinking maybe a bit more with 28", GRT shows 34.5 max at 85deg for this case volume and bullet so I knew I couldn't go up much more. I don't really care about going hot, but I also don't want to leave a lot on the table if there's a node still well below max.

 

[rijndael]

I was thinking maybe a bit more with 28", GRT shows 34.5 max at 85deg for this case volume and bullet so I knew I couldn't go up much more. I don't really care about going hot, but I also don't want to leave a lot on the table if there's a node still well below max.

I'd test the last 3 of the bottom row, with a larger sample size, and go from there.

 

[jxb]

Data from target above.


Based on responses I'll redo that bottom row and maybe add two more to the right.

I checked my other 6GT 26" and with 103 vtac's (I'm well into 34.x before any indication of pressure). Looks like I settled on a node around 33.8gn 2978fps for that one. My groups weren't nearly as consistent as this rifle but it did appear maybe a node there.

Thanks!

 

[rijndael]

ES and SD from 3 shots is not very useful data.

 

[Clancy]

Group 8 speed, do your seating at 200 or 300, start .004 off and back up by .002.

That is a good barrel, just needs a little nudge.

If it speeds up on you, back off to get back there and do another little feeler test with powder. Don’t try to run it too fast. It’s not a 6 Creedmoor, and that’s a good thing.

I think you’ve got a winner. That 8th group is on a lovely little node.

 

[jxb]

Group 8 speed, do your seating at 200 or 300, start .004 off and back up by .002.

That is a good barrel, just needs a little nudge.

If it speeds up on you, back off to get back there and do another little feeler test with powder. Don’t try to run it too fast. It’s not a 6 Creedmoor, and that’s a good thing.

I think you’ve got a winner. That 8th group is on a lovely little node.

Just to be clear, "start .004 off and back up by .002" back up is increase my off, like work from .004 off towards .012 off by .002 per. Right?

 

[jxb]

ES and SD from 3 shots is not very useful data.

It's collected, so I record it. I figure it's better than nothing and I'll get confirmation data as I settle and shoot larger sets. Compared to factory loads, these are stellar and the groups pretty much follow the data.

 

[rijndael]

It's collected, so I record it. I figure it's better than nothing and I'll get confirmation data as I settle and shoot larger sets.

I understand. I only commented because you highlighted it green, as if it was better that the data that surrounded it.

 

[jxb]

I understand. I only commented because you highlighted it green, as if it was better that the data that surrounded it.

lol, yeah that's actually code that auto backgrounds the lowest SD and I couldn't figure out where that was located. The form originated from another shooter that shared the original worksheets for folks to use, this is just part of it.

I like to see single digit SD and ES <20 but as I've learned here the target is what matters. I simply use SD/ES as an indicator of how my reloading is going.

 

[STOMP442]

I wouldn't rule out H4350 either. I recently did a work up on a GT with 109s and it really loved it.

 

[BondJamesBond]

Yea I would repeat starting at 33.2 and work up in .2 increments and maybe see what 34.1 looks like.
I like to see where the next scatter node starts or pressure starts whichever comes first
try 5 shot groups just to send more rounds thru it since still breaking in
Larry

 

[JFrank]

Those that read groups and don't mind sharing your input, it would be welcome. I'm new to this so lots of learning needed. Being a new rig I started low expecting to stay below pressure. I have never experienced all my groups in the ladder so small and with so little variation in position. Based on this output I'm thinking not only will I shift the loads to the right to get more fps and maybe find some indication of pressure, but also do it at 200 or 300 yards so I can better see the patterns. I'll also switch to front rest and tracking rear bag to try to remove me from the equation as much as possible. This other range I'll have possible wind, but concrete benches and solid target backers so I'm thinking that's the way to go. SD/ES are all good, but I purposely didn't include them, I'm looking for input on the groups and relation to each other initially.

This ^^^ plus a wind flag or two noting direction of wind and estimate wind speed without trying to correct your point of aim for wind.
Are your shooting on a clean barrel or not ?
Jim

 

[jxb]

This ^^^ plus a wind flag or two noting direction of wind and estimate wind speed without trying to correct your point of aim for wind.
Are your shooting on a clean barrel or not ?
Jim

Thanks Jim,

Above started with a new barrel, one to get on paper, the balance to get it near center and fouled like you see top row. Then I did my 30 round ladder test with three breaks to keep the barrel warm but not hot. I could always keep back of hand on barrel.

I generally clean barrels fairly well but not clean (maybe 80-90%) and I check with bore scope, then enough sighters to foul the barrel. My match barrels only take 1-3 rounds to settle. I might shoot more if it's really cold (below freezing), basically the goal is to foul the barrel and keep it in a warm but not hot state throughout testing.

I'm guessing you mean use flags and take notes for each group so a person can tell how much the group may be over due to wind. My goal would be to pick a day where the wind is light, 5mph or less but if there is wind try to shoot all in the group on the same flag state, or at least not switching.

Jeff

 

[JFrank]

You obviously have a good understanding, yes I use flags to help interpret results. A good example here for those in question, if not for flags I might have given up on a load thinking I had broken out but with flags i note the R-L quartering wind, I stayed with it and came out the other side still in the node at 31.6
Jim