What to expect when changing brass?

[DallyB09]

So I currently have a great shooting load in my 6.5 PRC. 56gr H1000, Hornady brass, WLRP, 156 bergers that’s around 3/4 min,but am only getting 2820 out of it. I’m stuck on if I should try different brass to pick up a little speed, but I don’t want to go through the entire load development process again. If I switch, should I expect same levels of accuracy with close to the same specs im running now?

 

[Vern400]

Recently shot the same load in a 6.5 creedmoor.
Hornady brass and S&B brass.

S&B was just over 50 fps faster. It was totally screwing me up at 500 yards. I was telling my brother " No, that was NOT me. It was a good pull". Then we matched up all the chronograph data, with the line of cartridges I was putting back in the box after shooting them. Come to find out the s&B was mixed in! It had a little bit less capacity, which drove the pressure up. The primers were showing more pressure in S&B than the Hornady cases. We marked the high right bad shots, and sent two more from Hornady cases.
2.56 inches group rather than 5.5 inch group including the S&B.

I didn't know he had mixed cartridges in the box. He's my brother so of course it was my fault.
"You can't just be shooting random s*** you know"
Me: "at least mark them when you do that"
"They're marked. That's what the headstamp is for".
Me: "Dam. They were pointing up, Goober"

It would probably take a powder reduction of about 0.4 grains to get the same velocity in S&B. What would the groups look like? I have no idea. But if you're doing Precision shooting, changing brass is going to change your load if case capacity changes with it.

 

[khuber84]

By switching from HDY to Lap, ADG or Peterson, you'll pick up a lil velocity due to the reduced capacity. Virgin VS fireformed shouldn't be much for than 10-20 fps different from first to second firing unless you have a deep chamber.

Whats keeping you from pushing the HDY brass harder? Are you nuking primer pockets at higher charges, clickers upon primary extraction? Bolt lift or ejector swipe?

 

[DallyB09]

By switching from HDY to Lap, ADG or Peterson, you'll pick up a lil velocity due to the reduced capacity. Virgin VS fireformed shouldn't be much for than 10-20 fps different from first to second firing unless you have a deep chamber.

Whats keeping you from pushing the HDY brass harder? Are you nuking primer pockets at higher charges, clickers upon primary extraction? Bolt lift or ejector swipe?

So with Hornady I shot a pressure ladder and got heavy bolt and ejector stamps at 57gr. Then shot groups at 56-57 in .2 increments. 56 shot little bug holes so that’s what I ended up with, just disappointed in speed. That 2820 is in a 24” barrel.

I’m shocked at these people stuffing 59-60 gr of H1000 in a case.

 

[khuber84]

So with Hornady I shot a pressure ladder and got heavy bolt and ejector stamps at 57gr. Then shot groups at 56-57 in .2 increments. 56 shot little bug holes so that’s what I ended up with, just disappointed in speed. That 2820 is in a 24” barrel.

I’m shocked at these people stuffing 59-60 gr of H1000 in a case.

Well, newer H1000 is slower than older stuff. I my 65 Saum, 58.8 gr N565 equals what 59.8 gr H1000 does, this is with a 156 tho

The Tikka action does not handle pressure like a 700 clone, I don't care what other say. Tikka barrels are slow too, so you're in a slow boat here just due to rifles traits. I have a 20in carbon aftermarket barrel, and I can run 2880 with 140s, anything over that is getting closer to pressure than where I wana be with lapua brass.

57gr psi out at mid 2800s does seem slow. Idk, I was running 156s at 3050 from the 26in barrel, chopped it to 20in and the same exact ammo was now at 2780, so I personally feel as the overbore index goes up, the velocity loss per inch goes up as well.

Swapping to better brass is likely only going to net you another 50-70 max working velocity. Is it worth it? That might be 0.2mil change at 500y.

 

[Splee]

Probably need to do the whole load development either way but you could try it, maybe we are all wrong. You could try different powder too. That’s what I’m going to next on my 6.5saum trying to get a little more accuracy. Also shooting the 156 Berger at just under 2,900 from a 22” barrel.

 

[MT257]

By switching from HDY to Lap, ADG or Peterson, you'll pick up a lil velocity due to the reduced capacity. Virgin VS fireformed shouldn't be much for than 10-20 fps different from first to second firing unless you have a deep chamber.

Whats keeping you from pushing the HDY brass harder? Are you nuking primer pockets at higher charges, clickers upon primary extraction? Bolt lift or ejector swipe?

So if I have a load with one brand brass but wanna change brands, is only thing that may need to be adjusted? OAL/CBTO should be remain unchanged correct?

 

[JFK]

So if I have a load with one brand brass but wanna change brands, is only thing that may need to be adjusted? OAL/CBTO should be remain unchanged correct?

When changing brass on a known good load I keep OAL/CBTO the same and drop down a few grains and work back up. I’ve had it go both ways. Sometime you end up right back where you started in terms of charge weight. Other times you end up with less powder in the new case and same or better velocity. It’s been my experience that when going from Hornady brass to just about any other type of brass I end up with a little less powder in the case. Always safer to work back up whenever you change a component.

 

[khuber84]

So if I have a load with one brand brass but wanna change brands, is only thing that may need to be adjusted? OAL/CBTO should be remain unchanged correct?

As JFK said, drop down at least a grain of powder charge, work back up. Keep same primers, seating depth and what not.

 

[Harvey_NW]

N565 and ADG will likely get you more speed, I pressured out at 59gr on new brass. 58 was sticky on fireformed so I dropped to 56.5 to get ~2900 out of a 21" suppressed Tikka barrel, and have been running smooth since with extremely tight vertical dispersion. I haven't tested it yet, but recently came across a couple posts about N560 being a shining star for velocity in the 6.5 PRC case, so I'll be trying to acquire some soon.

 

[khuber84]

Guys, N560 is a very high energy double based powder, produces great velocity. It's not temp stable at all though. You'll see 1 fps per degree of change from 0-80 degrees, above 80 it's about 1.5 fps per degree. Just keep this in mind when developing your hunting load in summer weather. I'd try ramshot grand before 560 myself.

 

[Harvey_NW]

Guys, N560 is a very high energy double based powder, produces great velocity. It's not temp stable at all though. You'll see 1 fps per degree of change from 0-80 degrees, above 80 it's about 1.5 fps per degree. Just keep this in mind when developing your hunting load in summer weather. I'd try ramshot grand before 560 myself.

I wondered about this, thanks for the info. I've found 565 to be very stable at .77fps/1°F from low 20's to high 80's. It's my bread and butter powder for the PRC.

 

[Mattman215]

When I switched my 6.5prc from adg to Peterson it was basically a full redo which was unfortunate but I couldn’t find adg brass at the time. I was using n565 also temp unstable.
However almost all powders I have used are not temp stable in my experience regardless what the manufacturer says.
I’m in Phoenix so 20 degrees up in the mountains to 118 in summer is very common.

 

[Sinistram]

I hate being "this" guy, but I'll bet the wet blanket in this conversation and advise you not to chase velocity. You have a load that's very accurate, and that matters more than speed. We've all been disappointed by velocity or accuracy in a given rifle/cartridge combo, but that's the hand you get dealt sometimes.

The literal answer to your question, restated from others in this thread, is there is a chance you could pick up some velocity with a different brand of brass, but you'd have to work up to it to be safe. There's also a chance nothing happens or you go backwards, and you waste components, time, and wear on your rifle - ask how I know!

A 3/4 MOA 156 grainer at over 2800 is very formidable.

 

[v.niner]

I hate being "this" guy, but I'll bet the wet blanket in this conversation and advise you not to chase velocity. You have a load that's very accurate, and that matters more than speed. We've all been disappointed by velocity or accuracy in a given rifle/cartridge combo, but that's the hand you get dealt sometimes.

The literal answer to your question, restated from others in this thread, is there is a chance you could pick up some velocity with a different brand of brass, but you'd have to work up to it to be safe. There's also a chance nothing happens or you go backwards, and you waste components, time, and wear on your rifle - ask how I know!

A 3/4 MOA 156 grainer at over 2800 is very formidable.

Second this. If tinkering with the ammo is something you enjoy, then go for it. If not, I don't see many scenarios where an extra 50-75 fps will be the deciding factor.