Load development question for the group

[Doughboy]

Greetings all.
I am new to this forum and new to priscion shooting, decent history with pistol and 3 gun.

I decided to start out with an RPR in 6.5 CM for cost, convenience and learning curve. Although I have reloaded pistol rounds for 10+ years I am also new to rifle reloading.

I am beginning to set up for ladder testing but I am considering switching muzzle brakes.

Will switching muzzle brakes effect harmonics enough to require re-ladder testing?

 

[spife7980]

It certainly it can. A barrel tuner works by shifting the weight like .02” inches or something tiny, whatever the thread distances is.

Here’s a graph of one rotation of the tuner weight

Half a rotation is a major change. Adding any difference in weight has the potential to throw your harmonics out of synch with your current load.

It could also be just fine if you have a real sweet shooting. Notice those group sizes- most would be pleased with any of them.

 

[christopher.dow]

It depends on what you’re testing.

If you’re ladder testing to find a range of powder weights where speed doesn’t change much, then it won’t matter. If your’re testing group sizes, then it will, as @spife7980 wrote.

I like the idea of gathering the speed data because it’s just about chemistry and physics (although Frank has shown extreme MV variations moving from good prone to poor bench shooting). When you include group size, the shooter becomes a biger factor. I think for someone who is new to this type of shooting, relying on objective data is important when sussing out why groups aren’t the desired size. So the graph you probably need is speed vs charge, not group size vs charge. When you know your speed is consistent and you see vertical stringing, then you can logically conclude it’s a shooter problem and not a load problem. Once your speed is consistant (SD < 10 & ES < 20), load about .015-.020 off the lands and then look at groups.

It’s all about removing unknowns.

 

[Doughboy]

Thanks! Very helpful info. I will post my progress and struggles along the way!

 

[Greg Langelius *]

I tried a homemade barrel tuner, and found that it could render very good (I.e. sub 1/2MOA at 200yd) accuracy. But I also found that it could go out of tune very easily when weather conditions changed significantly. Their adjustments were very sensitive.

Eventually, I gave up the testing and removed the tuner because I felt that I was being drawn into a dead end that was simply adding a big number of extraneous shots to my barrel log (I.e. The cost in extra bore wear wasn't really justified except for absolute accuracy applications like Benchrest.).

My final conclusion was to do my accuracy tuning by means of basic load development. There are so many influences that are external to load and barrel harmonics that even when getting the load development and harmonics down to extreme limits, the other conditions ended up negating much/most of the gains. Sometimes it is simply wiser to let some of that extreme accuracy fall by the wayside instead of burning up good barrels seeking the perfect target.

In my opinion, muzzle brakes have a real value, but I suggest they may be less of an advantage in sub-magnum chamberings. When applied to short action chamberings like 223 and 6.5CM, they are most advantageous with semi-auto rifles, where a rapid followup shot is more of a real possibility. Their worst singular disadvantage is noise.

Greg

 

[BigUn]

If you’re new to rifle reloading, you have a lot of reading to do! It’s not quite like pistols where you just load for a specific PF and here we go.
Highly recommend buying a Berger manual and reading the load development section. I’ve read numerous books on the subject and walt/bryan really did a good job- they made it effective, fast, and easy to understand.

 

[Doughboy]

I tried a homemade barrel tuner, and found that it could render very good (I.e. sub 1/2MOA at 200yd) accuracy. But I also found that it could go out of tune very easily when weather conditions changed significantly. Their adjustments were very sensitive.

Eventually, I gave up the testing and removed the tuner because I felt that I was being drawn into a dead end that was simply adding a big number of extraneous shots to my barrel log (I.e. The cost in extra bore wear wasn't really justified except for absolute accuracy applications like Benchrest.).

My final conclusion was to do my accuracy tuning by means of basic load development. There are so many influences that are external to load and barrel harmonics that even when getting the load development and harmonics down to extreme limits, the other conditions ended up negating much/most of the gains. Sometimes it is simply wiser to let some of that extreme accuracy fall by the wayside instead of burning up good barrels seeking the perfect target.

In my opinion, muzzle brakes have a real value, but I suggest they may be less of an advantage in sub-magnum chamberings. When applied to short action chamberings like 223 and 6.5CM, they are most advantageous with semi-auto rifles, where a rapid followup shot is more of a real possibility. Their worst singular disadvantage is noise.

Greg

I completely agree about muzzle brakes, when prone, I find it hard to stay on target, it is probably how I am building my position, poor recoil management.

 

[Doughboy]

If you’re new to rifle reloading, you have a lot of reading to do! It’s not quite like pistols where you just load for a specific PF and here we go.
Highly recommend buying a Berger manual and reading the load development section. I’ve read numerous books on the subject and walt/bryan really did a good job- they made it effective, fast, and easy to understand.

Thanks for the tip. I have a 5 year old Hornady manual and have been thinking about buying a new one. The Berger sounds loke a good choice. And I have read myself blind. I have read some of Bryan Litz (sp?) Stuff, is he the co-author you referenced? I really like his writing style.