H50BMG for 6.5PRC?

ajkellerusmc

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To me it doesn't matter that much. I always run enough bullet in the case to ensure good concentricity and the cartridge will feed properly. If I am not overly limited in COAL I'll run 20 thou- 50 thou. Velocity is affected but not largely by seating depth unless going extreme to extreme. I have had very good success with 140's at .100 off in several 6.5-284's tho so if you are inclined to test there, I would not discourage it at all.
BrentM, I conducted a satterlee/ladder test yesterday, posted the results below. Hopefully I did it right, I did find a good velocity node at 60.4gr and looks like I may have had another at 62.3 but shot #11 is goofy because of a drop in velocity. I think the Labradar read it wrong.

My Velocity is off the Hodgdon charts as they only show max charge of 57.7gr of H1000 with a 140gr Nosler BT at 2902fps. Berger gave me a starting load of 59.6 to 63.0. I took it up to 62.9gr with slight pressure signs starting to show with primer cratering so I think Im still at safe pressure. Look at my velocity and you will see I'm at 3200fps with 62.9gr. All loads at and above # 6 61.1 were compressed which is interesting when you study the target beginning with shot #6.

Interesting to Me is that shots were climbing until shot 6 and more so shot 7. Shots 7 thru 12 are not much different in vertical dispersion. Is this an Indication of an accuracy node? The target was set at 480yds.

So my conclusion and I would like Yours and others to weigh in as well, is this.
I have a good velocity node at 61.1 to 61.7 ( 3130fps to 3146fps) which is way below the max charge by Berger of 63.0gr so I get decent life out of my brass. looks like I may have another at 62.0 to 62.6 (shots 9,10 & 11 but #11 has the goofy velocity reading.

I welcome your thoughts and suggestions as to where to go next.
 

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BrentM

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I agree with your assessment of the chart. It is interesting and normal that the loads also show a good ladder at distance. I do the same thing, shoot for groups and velocity, it confirms a few things at once. The issue I have with ladders at distance is that the wind or shooter can really make a mess of things AND a distance ladder shows the load is tuned to that range and not always good multiple ranges.

OK, I personally would retest 61.5ish and 62.3ish with a 3-5 shot group and record ES/sd and accuracy at 500. I tend to think you are going to see more pressure show up at the higher node as those are pretty fast loads. Lets say you wind up at 3180 and 3135.... that is a 50 fps difference. At that point I would opt for the load that produces the lowest es/sd and best accuracy combo without beating the sheet out of the brass.
 

ajkellerusmc

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There is a 6.5 prc review I read online where a guy was loading it with us869. I haven’t loaded any prc roads up yet, but have been collecting materials. I plan on starting with retumbo and Sierra gamekings. If I can’t get that to work to my liking I will be going with h-1000 and 140 grain Berger hybrid. I did buy some US-869 just in case. Please let us know what you came up with
Elkaholic Bob, I posted some testing with the PRC if You want to take a look at it.
 

BrentM

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I welcome your thoughts and suggestions as to where to go next.

On a separate note.....I did a velocity test with N565 and 142's. Wanted to see how it compared to 1000 and rl26. I tested in .5 grain from 56-59. Based on that data I was able to do an initial check for the 135 in .5 from 58-60 and was right about where I thought it would be. So these are 5 shot ladders and the data is not that telling but it puts a guy in a general area to focus on. For example I will target the 135 test at 59.2-60.5 in .2. Probably do 2 shots for 14. Rounds.
 

ajkellerusmc

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I agree with your assessment of the chart. It is interesting and normal that the loads also show a good ladder at distance. I do the same thing, shoot for groups and velocity, it confirms a few things at once. The issue I have with ladders at distance is that the wind or shooter can really make a mess of things AND a distance ladder shows the load is tuned to that range and not always good multiple ranges.

OK, I personally would retest 61.5ish and 62.3ish with a 3-5 shot group and record ES/sd and accuracy at 500. I tend to think you are going to see more pressure show up at the higher node as those are pretty fast loads. Lets say you wind up at 3180 and 3135.... that is a 50 fps difference. At that point I would opt for the load that produces the lowest es/sd and best accuracy combo without beating the sheet out of the brass.
I did not mention the fact that my brass is virgin and with the ADG brand the necks were a very consistent .014” so I did not turn them. The tension or interference came in at .0045“ and I did not adjust that either. Will adjusting the tension down to .002 or .003 affect my accuracy or velocity down the road? I know it can affect ES and SD.
 

BrentM

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I did not mention the fact that my brass is virgin and with the ADG brand the necks were a very consistent .014” so I did not turn them. The tension or interference came in at .0045“ and I did not adjust that either. Will adjusting the tension down to .002 or .003 affect my accuracy or velocity down the road? I know it can affect ES and SD.
It can a little but you are not shooting a single group for sd yet. I personally would not shoot those groups on virgin brass. I think you will see pressure with the upper load so approach with caution.
 

ajkellerusmc

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I agree with your assessment of the chart. It is interesting and normal that the loads also show a good ladder at distance. I do the same thing, shoot for groups and velocity, it confirms a few things at once. The issue I have with ladders at distance is that the wind or shooter can really make a mess of things AND a distance ladder shows the load is tuned to that range and not always good multiple ranges.

OK, I personally would retest 61.5ish and 62.3ish with a 3-5 shot group and record ES/sd and accuracy at 500. I tend to think you are going to see more pressure show up at the higher node as those are pretty fast loads. Lets say you wind up at 3180 and 3135.... that is a 50 fps difference. At that point I would opt for the load that produces the lowest es/sd and best accuracy combo without beating the sheet out of the brass.
BrentM, I finally got out and shot these 2 groups with the 6.5PRC Berger 140 VLD Target with H1000 as You suggested. i was impressed with the higher load's accuracy. I have no signs of excess pressure except small cratering on the primer on 50% of the firing pins circumference which I think is due to poor fit and finish of the bolt face at the firing pin hole.

What would be my next step's? adjusting the powder charge? or a 20 round seating depth test like Berger recommends?

I calculate my Moa at .408 with the 2 1/8" group, these were fired at 520Yds. I disregarded the fly ball near the orange bulls eye as I pulled that shot.

Your thoughts?
 

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BrentM

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BrentM, I finally got out and shot these 2 groups with the 6.5PRC Berger 140 VLD Target with H1000 as You suggested. i was impressed with the higher load's accuracy. I have no signs of excess pressure except small cratering on the primer on 50% of the firing pins circumference which I think is due to poor fit and finish of the bolt face at the firing pin hole.

What would be my next step's? adjusting the powder charge? or a 20 round seating depth test like Berger recommends?

I calculate my Moa at .408 with the 2 1/8" group, these were fired at 520Yds. I disregarded the fly ball near the orange bulls eye as I pulled that shot.

Your thoughts?
I’d prolly test .2 above and below that load and then look at seating. If it’s consistent I’d be inclined to say it’s good and probably leave it. I’m not a huge fan of burning powder and barrels to get .2 more accuracy.
 

ajkellerusmc

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I’d prolly test .2 above and below that load and then look at seating. If it’s consistent I’d be inclined to say it’s good and probably leave it. I’m not a huge fan of burning powder and barrels to get .2 more accuracy.
Thanks, I will try that next. I appreciate the input.
 

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