Velocity ?

[uplander]

Hello,
I have been reloading for a couple of years now and I recently purchased a chronograph. I tested some of my 7mm mag loads this weekend and I'm not getting anywhere near the value printed from load manual. I'm shooting a stock Howa 7mm with a standard barrel. My load is 64.1gn RE-22, CCI250, and 168 gr Berger touching the lands. I'm getting about 2750-2760 fps out of this load. I tried some at 65 grns and that is giving me about 2800. 65 is the max stated from Berger with RE22. Now, I realize that the barrel that generated that out of quickload with 24 or 26 inches and I'm sure it was a custom barrel. The max stated load based on that data is 3,000 fps. I'm not seeing any pressure signs and the primers all look good at 65 grains out of mine. I'm just looking for a little advice as to what is going on or if I can push the loads any more.

Thanks,
Justin

 

[royinidaho]

I'd say you have room for a bit of increase in velocity.

I don't know what you call pressure signs? Pressure signs for me begin with sticky extraction and/or an extractor mark on the case head. These indication should indicate pretty high pressure. Higher than an sensible person would wish to approach.

When increase in velocity increases are get pretty small for an increase in powder weight its another indication that its time to not increase charge weight any further.

These are pretty poor indicators, that is, not reliable or possibly even "safe" and definitely not laboratory quality but they R indicators.

Use your own judgement but don't be as silly as me.

Unless you are harvesting animals at more than 600 yds or so it doesn't make that much difference anyway.......

 

[uplander]

600 yds would be my limit, but I'm thinking that, with these bullets, I think I may need to spin them a little faster to get some better grouping. It may or may not hold true, but I would like to try it. As far as the pressure signs, I'm not getting any sticky extraction or extractor marks. The cases seem to be holding together well. I will try and work some up to see what I get. Thanks for the help.

 

[backwoods83]

You could try 70-72grns of H1000 or 62-64grns of hybrid 100v. Either should get you to 2950+, I'm not a big RE22 fan its to sensative in temp and lot# change.

 

[uplander]

I've tried the H1000, but rifle didn't like it....may have to give it another whirl. I used some IMR4831's on some nosler and that seemed to work. Has anyone had any success with that in a 7?

 

[backwoods83]

I have used H4831 which is a little slower than Imr4831 but I'm guessing about 62 or so grains of it would do well, probably more with you OAL out that far.

 

[rscott5028]

A lot of variables can affect the velocity you get in your rifle.

Run a ladder test and watch for signs like Roy stated.

If the hotter loads don't prove to be notably more accurate, then it's a non-issue.

If a max load does the trick, then you have to be careful that they don't become dangerous with changing conditions.

I've used RE22. But, like backwoods stated, it's not your most temp stable powder. H4831sc works for me. But, I'm not trying to squeeze out the most velocity either.

-- richard

 

[rscott5028]

600 yds would be my limit, but I'm thinking that, with these bullets, I think I may need to spin them a little faster to get some better grouping. It may or may not hold true, but I would like to try it. As far as the pressure signs, I'm not getting any sticky extraction or extractor marks. The cases seem to be holding together well. I will try and work some up to see what I get. Thanks for the help.

As for spinning them faster... you can research the math at JBM. But it takes a LOT of velocity to overcome a twist that's too slow.

If you get improved accuracy from increased velocity, it's likely due to improved harmonics.

-- richard

 

[uplander]

I've done the ladder test already and haven't seen any noticable signs of pressure at all. Accuracy has been decent at 100 yds, but they seem to open up more than they should at 200. I want to try pushing them a little faster to see if it will close them down a little bit (that is what I meant by spinning them faster). I've also heard that those Bergers don't really start hitting their sweet spot till 300 yds plus...not sure about that though.

 

[rscott5028]

Aside from increased horizontal dispersion due to wind and increased vertical dispersion due to MV variability, there are a lot of factors that can grow or shrink groups at longer distances not the least of which is parallax.

-- richard