Long range load development at 100 yards.

[David Christian]

So I ran a test on my 6.5 CM. I have been shooting Hornady Factory 147 ELD Match with 7 twist and getting amazing results at 2760 fps. See below for H4350 on 147 ELD. I am thinking 39.7 or 39.9 grain is best in vertical. I did not get a flattening of the Velocity until 40.7 and 41.1 but the vertical dispersion is greater. Unfortunately the 39.9 is running 2694 fps. The 2760 fps of factory would have come in around 41.3 grains.

Had a couple of oops. at 39.9 I ended up with the second round at 2716 so I shot a 4th to bring it back to the average. The high hole is the 2716. The other 3 are in the small group.

At 41.1, I shot a 41.5 round.

Jeff

I might bracket around 39.9. Up and down by .1 grains from 39.7 to 40.1, 5 shot groups on each powder charge.

 

[David Christian]

View attachment 1056439 View attachment 1056440 View attachment 1056441 Hello guys, could you please give your opinions on the following groups.
Howa .308 Varmint barrel 1:10
GSC 130g monolithic copper with drive bands
Lovex 73.5 aka Accurate 2460
Federal magnum primers
Lapua brass
The last round on the 50g group had a VERY small raised crater around the primer indentation
The second from last group should read 49.7g

I don’t like any of your powder charge results. No real pattern between successive target results and your ES’s are all over the board. I suspect something is off in your loading process or your chrono is going wacko. You should not have those spreads in your speeds within the same powder charge.

How confident are you in your loading technique, scale, brass consistency, etc?

What type of chrono are you using?

 

[Lillico]

Thanks David, I use a beam scale for powder, Wilson neck bushing die and very consistant cases and bullets.
I only have access to a Caldwell Chronograph.
I thought the last two groups had potential, especially the 49.7 which had flattened out velocity wise and had low ES.

 

[Rogmay]

I might bracket around 39.9. Up and down by .1 grains from 39.7 to 40.1, 5 shot groups on each powder charge.

Jeff, would do like David says with groups of 5, but I would also take them out to 300yrds, then when I find the one that groups the best, then test seating depths with that load at 300yrds.

 

[Jeffrey Curl]

I might bracket around 39.9. Up and down by .1 grains from 39.7 to 40.1, 5 shot groups on each powder charge.

Thank you

 

[David Christian]

Thanks David, I use a beam scale for powder, Wilson neck bushing die and very consistant cases and bullets.
I only have access to a Caldwell Chronograph.
I thought the last two groups had potential, especially the 49.7 which had flattened out velocity wise and had low ES.

49.7 by itself might be decieving. That powder charge does not line up with either 49.4 to the left or 50.0 to the right. If you draw a line between the center of those three targets, it slopes upward quite a bit. Under the Cortina method, you are looking for 2-3 powder charges in a row that show as little slope as possible, meaning you found a “flat spot”.

Any chance you can connect with someone that has a magneto or labradar to confirm your ES numbers? An ES of 11 over 3 shots Is still gigantic. I suspect an accuracy issue in your chrono.

Let us know what you come up with.

DC

 

[IdahoSharpshooter]

I put nearly as much importance on the group shape as size, as long as it is comparable. Give me a nice round 1moa target over a 3/4moa that is four in a bug hole and one in the next zip code any time. I can never replicate the 4&1 on a consistent basis.

 

[seymour fish]

View attachment 1056439 View attachment 1056440 View attachment 1056441 Hello guys, could you please give your opinions on the following groups.
Howa .308 Varmint barrel 1:10
GSC 130g monolithic copper with drive bands
Lovex 73.5 aka Accurate 2460
Federal magnum primers
Lapua brass
The last round on the 50g group had a VERY small raised crater around the primer indentation
The second from last group should read 49.7g

Your last 2 groups show roughly the same elevation and could be construed as a node perhaps 0.4 grains across, If in fact you have reached pressure. We’re there any other signs ? Since none are desirably tight and seem to want to scatter, it begs the question are you seating these at least .050 OFF the lands, or more. If not, correcting that should help. You may not need a Mag primer with that ball powder unless cold out. Some bbls don’t like the monolithics, and some copper up badly with them, so .......if you want a light for caliber, the 125 gr Nosler would likely be much easier to tune

 

[Lillico]

Seymour many thanks for your constructive advice and offering a possible area for improvement i.e. 0.050" off the lands. These monolithic coppers are very long!
No other pressure signs apart from one primer cratering on the last shot, not visibly, only detectable with touch.

I have moved the bullet back from the lands another 0.012". That reduced the lateral spread from 1.9" to 1.3", with the group showing no vertical movement.

I'll follow your advice and try a spread of 0.033 to 0.039 further off the lands, thus taking the bullet to around 0.050" stand off.

If I can get the groups to come in, I'll try a -0.4g to +0.5g test and check for pressure again.
Again, many thanks.

 

[seymour fish]

Seymour many thanks for your constructive advice and offering a possible area for improvement i.e. 0.050" off the lands. These monolithic coppers are very long!
No other pressure signs apart from one primer cratering on the last shot, not visibly, only detectable with touch.

I have moved the bullet back from the lands another 0.012". That reduced the lateral spread from 1.9" to 1.3", with the group showing no vertical movement.

I'll follow your advice and try a spread of 0.033 to 0.039 further off the lands, thus taking the bullet to around 0.050" stand off.

If I can get the groups to come in, I'll try a -0.4g to +0.5g test and check for pressure again.
Again, many thanks.

Lillico, very happy with your results. Work that plan ! Seymour

 

[Jeff361]

Hello Erik and the rest of the knowledgeable people participating in this thread. I have been using the OCW method for a few years with reasonable success and am now looking to further refine my process using Erik's procedure and hopefully shoot better at longer distance. I just got a new rifle for PRS type comps. Surgeon 591 , 6.5 creedmoor, Kreiger M24 1:8,Lapua Brass, H4350, Br2. My load needs to be loaded to magazine length. Once I complete charge weight testing I will do seating length testing working back from maximum magazine length. I just completed the first part of charge weight testing and am a little unsure of how to proceed next. To me it looks like 40.0-41.0 is a node. However, 42.0 has the lowest SD and the velocity change between 41.0 and 41.5 is the flattest. Based on the groups and the numbers any suggestions on where to go next with this load?

 

[seymour fish]

Hello Erik and the rest of the knowledgeable people participating in this thread. I have been using the OCW method for a few years with reasonable success and am now looking to further refine my process using Erik's procedure and hopefully shoot better at longer distance. I just got a new rifle for PRS type comps. Surgeon 591 , 6.5 creedmoor, Kreiger M24 1:8,Lapua Brass, H4350, Br2. My load needs to be loaded to magazine length. Once I complete charge weight testing I will do seating length testing working back from maximum magazine length. I just completed the first part of charge weight testing and am a little unsure of how to proceed next. To me it looks like 40.0-41.0 is a node. However, 42.0 has the lowest SD and the velocity change between 41.0 and 41.5 is the flattest. Based on the groups and the numbers any suggestions on where to go next with this load?

Decent from 40.5-41.5. Might look at 0.1 gr increments across the middle 2/3

 

[JimSC]

I did a load test yesterday on Sierra 142's with H4831SC in a .260 Remington with a new 100 round count 30 inch Shilen 1 in 8 twist barrel. Due to a chrono error at 43.3 and 43.6 I have no data. but the following velocities were recorded

43.9 gn 2749 FPS SD 49
44.1 gn 2762 FPS SD 35
44.4 gn 2769 FPS SD 7
44.7 gn 2804 FPS SD 18
45.0 gn 2816 FPS SD 11
45.3 gn 2818 FPS SD 32

seating was at 2.250 base to ogive and .025 off lands.

I will only have one chance to do a seating depth test before a 800 yard match should I test depth test @ 44.4 which had the lowest SD or 45.0 which had a slightly higher SD but the test groups between 44.7 and 45.3 only had a 14 FPS differential. The alternative would be leaving the depth at 2.250 and doing a velocity test using 44.3 - 44.4 - 44.5 and a velocity test using 44.9 - 45.0 - 45.1

Targets were shot in the afternoon at 88F and a heavy boiling mirage with 0 - 3 mph winds. Not my ideal testing environment but I had to work with what I had after a solid week of rain

thanks in advance for any replies



left side on target 2 was cut off on the scanner, top is 44.4 and bottom is 45.0

 

[jp]

Shot this Today.. which ones would you choose? No chrony today just load and seating depths

 

[abersfelderami]

33.2 gr / -.04

 

[Rogmay]

33.2 @ .011, the jammed group shot a little high, the next three you can stack on top of each other, take the one in the middle!

 

[lazyMlazyK]

Shot the .22-250 at 322 yards last night. 13 rounds, starting at 36.3 gr. H380, ending at 39.9 gr. Worked up in 0.3 gr. increments. Bullet was Nosler Varmageddon 55 gr. flat base ballistic tip p/n 17240. Was not shooting groups, just a ladder. What are your thoughts? I’m thinking 8, 9, and 10, or 11, 12, and 13 look like nodes? Chrono wasn’t working or I would have velocities to add here as well.

 

[daniel brothers]

I’m thinking 8, 9, and 10

 

[SGK]

Sample sizes of 1. What do you expect those samples to tell you about how/where your rifle shoots and with what degree of confidence?

 

[lazyMlazyK]

Sample sizes of 1. What do you expect those samples to tell you about how/where your rifle shoots and with what degree of confidence?

Just hoping to narrow down a starting point for load development. If load 9 tells me I might have some decent grouping, I can load up 3-5 rounds of load 8, 9, and 10 to continue development. Is that a bad method? I’ve always just started by shooting groups in 0.5gr increments but wanted to try something different. Isn’t this type of ladder test supposed to give a guy an idea of where accuracy nodes might live for a certain gun with a certain load, even with a sample size of 1?