7mm PRC & N570

[philcox]

A lot of folks would be surprised to see the actual pressures they are hitting. I think a good chunk of handloaders are exceeding Saami without realizing it. Others (me included) realize it and monitor for signs that it is getting too high. Stiff bolt lift, blown primers, etc.

Yep. I have been doing the "monitoring". There is no load that I run where I am getting any "signs". my RL26 load: 168 LRX, 3.20 COAL, 67.5 g RL26. 22' Barrel. GRT says pressure is 69074 and SAMMI max is 63817. I have heard that GRT has a "fudge factor" so wondering what QL would tell me. I likely need to do some "hot load" testing to see if the California A-Zone temps (100?) are going to affect my loads. Guess a set of "hot pockets" will be used to get a similar temp.

 

[TxLite]

Following up. Took it out to 1000 today and it shot fine. Winds were all over the place. Groups below were at 900 and 1000. Velocity went up ~30fps between March to now. Roughly 30 degree difference in temperature.

 

[BossGobbler2024]

Following up. Took it out to 1000 today and it shot fine. Winds were all over the place. Groups below were at 900 and 1000. Velocity went up ~30fps between March to now. Roughly 30 degree difference in temperature.

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Great shooting and awesome looking range!

 

[BossGobbler2024]

I posted this on another thread but it seems appropriate here also.
I have shot a 3 shot ladder at 100 yrds with my gunwerks 18 inch 7 PRC with Elite iron suppressor using N570 this weekend. Results are fair nothing outstanding yet. I shot from 66.4 gr to 70.1 (book max showing 68.7gr). I have not seen any signs of pressure. I shot 27 rounds on Friday up to 69.0 gr and ran out of range time as it closed. I had a decent group at 68.4 (2743 FPS) so I loaded 10 rounds with this charge weight at BTO 2.620 (0.050 jump and 2.590 (0.080 jump) and shot those today with the remaining loads I had upto 70.1 grns. I decided to clean the barrel since its still new. I shot 3 rounds of Factory outfitter 160gr CX to start today and foul the barrel. This ammo doesn't shoot well in this rifle so its good for something. I will attach the targets but nothing is extra special velocity is very near 2800FPS with 70.1grns N570. I will say as noted previously this powder is definitely large log sized kernals and I tapped them down so as not to crunch em. This will definitely be more an issue as charge weight goes higher. I will load a few more with more higher charges to see where pressure signs occur but I think I will load some more rounds at 70.1and 69.09 with same seating depth and try to seat deeper if I can to increase the jump to try and tighten the groups. The stats sure seem to be more favorable at the higher chargers. These are shown on the targets. NOTE: these are all 168 gr LRx bullets. I had put TTSx down in error. The squares are 1 inch on the targets.

 

[TxLite]

Great shooting and awesome looking range!

Wish it was local to me. Visiting a friend

 

[BossGobbler2024]

I found a 7prc file on discord. I’d also modified 7 blaser on GRT and got close but the 7prc discord file has been accurate for

I found a 7 PRC file on discord. I figured out how to import it. Now to figure out how to use it. How do you measure the case capacity with water? simply zero the scale with an empty fired case and fill with water?

 

[TxLite]

I found a 7 PRC file on discord. I figured out how to import it. Now to figure out how to use it. How do you measure the case capacity with water? simply zero the scale with an empty fired case and fill with water?

Pretty much as you described. I got an empty sized case and seated a spent primer so water wouldn't leak out of the primer pocket. Weighed the case empty, zero'd the scale, then added water until full.

Add in your various other particulars (case length, seating depth, bullet of choice, barrel length, etc.) and then let 'er rip.

Keep in mind the program is just approximating pressures and some powders are better calibrated than others, but it will get you ballpark. It has been pretty accurate so far for my uses.

 

[BossGobbler2024]

Pretty much as you described. I got an empty sized case and seated a spent primer so water wouldn't leak out of the primer pocket. Weighed the case empty, zero'd the scale, then added water until full.

Add in your various other particulars (case length, seating depth, bullet of choice, barrel length, etc.) and then let 'er rip.

Keep in mind the program is just approximating pressures and some powders are better calibrated than others, but it will get you ballpark. It has been pretty accurate so far for my uses.

Thank you. I measured somewhat lower amount of case volume than sammi spec for my peterson brass.

 

[TxLite]

Thank you. I measured somewhat lower amount of case volume than sammi spec for my peterson brass.

My Peterson came in at 80gr. 79.3 for my ADG.

 

[BossGobbler2024]

My Peterson came in at 80gr. 79.3 for my ADG.

The most I got was 81.26 and usually between 80.0 and 81 for Peterson ready to load prepped brass and spent primer inserted.