20" 7 PRC+p Velocities

[CCooper]

After a long wait I finally received my 7 PRC+p back from the smith and got some time to shoot a couple ladders for pressure as there isn't a ton of data out in the wild- figured I'd share if anybody is interested.

The Build:
Defiance Anti-X LA
Proof 20" 5R 1:8 Sendero Contour
AW Chamber w/ +P
TI Pro 4 Brake & Scythe TI Can
Triggertech flat shoe set @ 1.5#
XLR Element 4.0 Folder Chassis
NF NX8 4-32 in NF rings

180 ELDM, Virgin ADG Brass, and Fed 215M primer used for all testing.

All shots were fired over my Garmin- 60 degrees F, 600' ASL with the Scythe on:

Notes:
Case fill was poor with the N-560, about perfect with H-1000.
N-570 in the upper range was easily over 100% and the kernels were settled with an electric razor as they were funneled slowly. Seating will likely need to be >.060 off jamb with the full house loads (anything over 73 gr).

CBTO @ Jamb was 2.665 w/ my Hornady comparator.

Factory Precision Hunter and Match shot 2670-2700 and grouped like hot garbage +2 MOA- but these are seated quite deep. The ladders shot closer to jamb certainly showed accuracy promise.

At the end of the N-570 Ladder, chamber was sitting at 85 rounds fired.

POWDER	CHARGE	FPS	SEATING OFF JAMB	NOTES
N-560	64	2643	0.06
N-560	64.5	2646	0.06
N-560	65	2689	0.06
N-560	65.5	2703	0.06
N-560	66	2724	0.06
N-560	66.5	2755	0.06
N-560	67	2801	0.06
N-560	67.5	2810	0.06	Stiff Bolt Lift
POWDER	CHARGE	FPS	SEATING OFF JAMB	NOTES
H-1000	68	2748	0.06
H-1000	68.5	2771	0.06
H-1000	69	2796	0.06
H-1000	69.5	2801	0.06
H-1000	70	2840	0.06	Stiff Bolt Lift
H-1000	70.5	2859	0.06	Very Stiff Bolt Lift
POWDER	CHARGE	FPS	SEATING OFF JAMB	NOTES
N-570	68	2625	0.06
N-570	68.5	2618	0.06
N-570	69	2642	0.06
N-570	69.5	2684	0.06
N-570	70	2720	0.06
N-570	70.5	2719	0.06
N-570	71	2733	0.06
N-570	71.5	2767	0.06
N-570	72	2789	0.06
N-570	72.5	2830	0.03
N-570	73	2868	0.03
N-570	73.5	2857	0.03
N-570	74	2888	0.03
N-570	74.5	2891	0.03	Stiff Bolt Lift
N-570	75	2947	0.03	No Pressure Signs

 

[CCooper]

Mods- please move to reloading forum- my bad
@Team4LongGun
@fngTony

 

[Harvey_NW]

Badass build. I'd do a 10 shot group at 73-73.5 of N570 and if it holds tight, freakin send it. 68-69gr H1000 would probably be a solid load too after brass is formed and barrel speeds up a bit, if it grouped any better.

 

[Lemhi]

Interesting results. I’m running 4831sc in my 18” and it shoots 175’s @2830 with room for more speed if I wanted it. I need to try some 180’s one of these days.

 

[TxLite]

Did you happen to do any testing before the +p?

My 18” non +p is sending 180 hybrids at 2830 with 73.0 n570 and no signs of pressure with the scythe attached

 

[Lemhi]

Did you happen to do any testing before the +p?

My 18” non +p is sending 180 hybrids at 2830 with 73.0 n570 and no signs of pressure with the scythe attached

I didn’t. I’m pretty hesitant to push it much harder though as I’m sitting at 7.4lbs with the nxs 2.5-10 and TBAC ultra 5. It’s a bit rough on the shoulder with the super thin recoil pad

 

[TxLite]

I didn’t. I’m pretty hesitant to push it much harder though as I’m sitting at 7.4lbs with the nxs 2.5-10 and TBAC ultra 5. It’s a bit rough on the shoulder with the super thin recoil pad

Mine is just over 8lb and definitely lets you know it’s there but very tolerable. The vg2 recoil pad is very thin as well

 

[Forrest.billy]

Just for comparison, I’m getting 2910 out of a 20” 7prc with 66gr of RL 26 and 175s a couple grains below pressure.

 

[CCooper]

Did you happen to do any testing before the +p?

My 18” non +p is sending 180 hybrids at 2830 with 73.0 n570 and no signs of pressure with the scythe attached

No testing was done prior to the +P.

 

[haydenmp]

Interesting data. I had the same results with factory ammo. Have a similar build, with a couple different components. Main differences would be Carbon6 20", peterson brass, UM reamer, cci 250, jumping .077.

Tried n555, h4831sc, n560, h1000, n570. I found n560 seemed to work the best in this one in terms of case capacity, speed, and groups. n555 showed pressure with lower case fill, and n570 was full case capacity before pressure. I didn't use a drop funnel or try compacting it. I wouldn't use this as a reference, this is just what I saw out of this one.

Have shot with 4 similar other 7PRC+p builds varying in length from 20" to 24", using the same bullet. All shoot well. They use h1000, h4831sc, n560. One uses Retumbo.

Thanks for posting this.

 

[CCooper]

Interesting data. I had the same results with factory ammo. Have a similar build, with a couple different components. Main differences would be Carbon6 20", peterson brass, UM reamer, cci 250, jumping .077.

Tried n555, h4831sc, n560, h1000, n570. I found n560 seemed to work the best in this one in terms of case capacity, speed, and groups. n555 showed pressure with lower case fill, and n570 was full case capacity before pressure. I didn't use a drop funnel or try compacting it. I wouldn't use this as a reference, this is just what I saw out of this one.

Have shot with 4 similar other 7PRC+p builds varying in length from 20" to 24", using the same bullet. All shoot well. They use h1000, h4831sc, n560. One uses Retumbo.

Thanks for posting this.

What kind of speeds are you seeing with your and the other's combos?

 

[haydenmp]

I'm running 2940. I was at 3000 but backed it off.
Speeds range from 2860 to 3050 depending on barrel length and powder. about 3000 ft elevation.