7 PRC reloading with H4831SC

[Don Rackley]

Just curious if anyone has seen velocity differences from what the Hodgdon website shows.

I loaded up some new ADG brass for my 7PRC with H4831SC. I started at 62.1g with 162gr ELD-M bullets and Federal LRMag primers and shot them from a Proof 24" new barrel. The website shows 64.2gr of H4831 should yield 3,018fps. I got an average of 2,906 fps from 5 shots off my MagnetoSpeed chronograph with no pressure signs or hard bolt lift.

I did get some 0.50MOA groups at 63gr and 2,860 fps, but thought I would get more velocity. I'm going to keep going carefully on charge weights to check velocity and watch for pressure.

I would like to try some H1000, but an 8lb keg is very hard to get........

 

[VinceMule]

"I'm going to keep going carefully on charge weights to check velocity and watch for pressure."

+1!

I would also try a cci 250 primer, for giggles and grins!

 

[California hog hunter]

I'm running 66.5 of h4831 in a sherman max with 151 Cayuga. That loads 3189 fps the prc has more capacity. You should get more out of it.

 

[eshorebwhntr]

In my experience H4831 or 4831SC are notorious for what you've experienced. You'll get a load that shoots really well with no problem but it will not light up any chronographs.

 

[Nevrsummr]

Really appreciate this post. Building a 7prc that should be done in 4 weeks and the LGS has 8 lber of 4831sc. Was on the fence about buying it. But i think ill pass now.

Couple thoughts here. If you arent seeing pressure signs ( and you know what to look for) keep going up. 4831 is a faster powder than h1000 so i wouldnt expect faster results from slower powder unless using more gr powder so think about case fill there.

Please keep us posted.

 

[Don Rackley]

As mentioned earlier, I loaded more shells with higher charges and shot them yesterday, same rifle, bullet primer, just went heavier on powder.

Much happier....

Stepped from 64.2gr H4831SC up to 66.3gr. No pressure signs, no heavy bolt lift so I think there is more headroom to explore, but got real tight groups at 65.4, 66.0 and 66.3, plenty good enough to kill deer or elk. Will go see what is does at longer ranges next month.
Got velocities below (5 shot average) from Magnetospeed V3.

64.2 gr - 2,878 fps
64.5 gr - 2,902 fps
64.8 gr - 2,924 fps
65.1 gr - 2,936 fps
65.4 gr - 2,936 fps
65.7 gr - 2,960 fps
66.0 gr - 2,967 fps
66.3 gr - 2,981 fps

 

[7wssm]

Retumbo would probably get you into that 3000+ fps

 

[buckbrush]

Another 50 fps isn't going to change much. Looks like you've found a good load.

 

[Don Rackley]

Another 50 fps isn't going to change much. Looks like you've found a good load.

I agree with you, no animal is going to able to tell the difference and ballistic differences to 1,000 yds are immaterial.

 

[Dmagna]

to each their own when it comes to reloading, but I always reload to the cartridges full potential. Seems like this is leaving a lot on the table.

 

[Dmagna]

I am almost 100 fps faster with a Berger 180 hybrid in the prc. I shoot a 175 eldx out of a 280 ai in 24" barrel at 2950. Magnums need to be pushed.

 

[Phil Rizzo]

I am almost 100 fps faster with a Berger 180 hybrid in the prc. I shoot a 175 eldx out of a 280 ai in 24" barrel at 2950. Magnums need to be pushed.

Higher load density, potentially tighter SD etc..

 

[AZ82New]

I'm running 66.5 of h4831 in a sherman max with 151 Cayuga. That loads 3189 fps the prc has more capacity. You should get more out of it.

Have you taken any game with that bullet?

 

[Chapultepec]

Using H4831sc w 195 g Berger. Working load test up. Started at 57 w .3 increments. Was down below 2500 for first 3 shot group w57g. Ended up today at 60.2g with 2600 fps is all. Not compacted and no pressure signs. Will work up in .2 grain increments from here on one t. CA mesa 22".

Cheers from idaho