28 Nosler barrel 'sped up'

[bodywerks]

This cartridge has been interesting to me. It's the first time I read discussions of barrels speeding up after 'x' amount of rounds.
When I first got the rifle I found an accuracy node pretty quickly of 79.5gr retumbo under 195 bergers on an 'almost' saami spec chamber. Was getting 3050 and driving tacks out to 1k. Fast forward to my hunt, and about 100 rounds in. Went to verify dope, and glad I did, kinda. Found that I was about 7" high at 700 yards. Didn't have my chrono with me at the time, but math calculates it to be about 3125 - 75fps speed up. Of course, with that speed up, my accuracy went down. Went from 4"groups at 1k to 7"groups at 700. No time to work up another load, I just dealt with it. Still got the job done at 575 yards, but now I feel like I need to completely rework my load, on a barrel that already has 1/4 of it's life burned through it. Is this the norm for fast magnum chamberings? If so this might be my last. In the meantime, should I just try to find a load that gets me back to that magical 3050fps, or should I do a complete re-work up?

 

[stello1001]

If it were me, I'd try to down your charge a bit and look for your initial speed of 3050. See how that works and groups for you. If not too well, you might have to start load development again from scratch! But more than likely, it will be good once you get back again to 3050!

 

[Jimgal62]

If it were me, I'd try to down your charge a bit and look for your initial speed of 3050. See how that works and groups for you. If not too well, you might have to start load development again from scratch! But more than likely, it will be good once you get back again to 3050!

I would run five rounds at 3050 FPS with the same jump and expect similar results as before.

Assumes you know how many grains to drop from previous load development and insignificant throat erosion.

You can verify throat erosion prior to the test using Hornady gauge tool.

 

[CanSniper]

Yep, just played the same game with a 300wm. Back down your charge to run the same velocity as before. I bet you will be back in your sweet spot. Make sure your increase in pressure is not due to a carbon ring build up.

 

[demonjigger]

What are your barrel specs and cleaning regiment?

 

[bodywerks]

Brux 8.5 twist, 26 inches. I keep copper in my barrel for the most part. I only did an initial break in cleaning where I pulled the copper out after each round for the first 5, then every other for the next 10, then after every 5 shot group for three groups. Now I just run a patch through it with some Hopps 9 when I feel sorry for it. In my experience, rifles tend to shoot more consistent when you don't over-clean the barrel. Going on about round 175 with this barrel now. Probably going to give the barrel a full cleaning before I start load development again.

 

[Deleted member 10043]

You just just sent yourself down the rabbit hole here. I would bet that 1) your 4" group(s) @1000 was isolated and occasional, 2) always recheck zero before a hunt, 3) clean the rifle more often. Not mention to zero at your hunt. This has little to nothing to do with some preceived node. Why people develop a perfectly good load then later on down suspect that load when they get a different result is beyond me. If you have a rifle that constantly needs load development than WTF. Find the real problem.

 

[bodywerks]

Everyone has their idea on what is considered proper barrel care. This isn't a question of barrel care, and I haven't had to "constantly need to redevelop my load". The gun only has about 175 rounds down the pipe, and the first 90-100 were a non-issue and very accurate.
After starting this thread I have read that it is VERY common for(especially magnum-chambered) barrels to speed up. That is the case here. I have cleaned my barrel many times more than many competitive shooters do in my 175 round count. Every rifle I have had previously always shot more consistently accurate with a copper-fouled bore.
And I did re-check my zero before my hunt, as well as my dope. put it right through the heart at 575 yards on a coues deer in high winds.

 

[Deleted member 10043]

I appreciate you providing more detail. But your original post is stating you are already through 25% of your barrel life.

 

[lennyo3034]

It’s a pain in the ass sometimes. My 6 CM barrel picked up 160fps! from initial load development. Putting me above most speed limits and significantly reducing accuracy. I had to move to a slower powder when completely redoing load development.

 

[generalzip]

I don't even do load development until I have 200 rounds on my barrels because of exactly this. Go have fun at the range plinking long range, practicing different positions, etc. Once it's broken in then do load work. I've found barrels tend to shoot better after 100 rounds through them at least to wear down and smooth everything up.

 

[bodywerks]

I appreciate you providing more detail. But your original post is stating you are already through 25% of your barrel life.

Well, not quite 25% I guess. But many are speculating only 1500-1800 rounds of useful life in this chambering. I guess I'll find out eventually...

 

[generalzip]

I’m Only expecting 1000 rounds barre life. 1800 is unrealistic. My 6 creedmoor doesn’t even do that.

 

[Bradu]

800 rounds is what one of the well known smiths that builds a bunch of them is saying for the 28 nosler. It all depends on what is acceptable for accuracy though.