Thread: Same load increased velocity 🤔

Problem solved.
I thought I gave my rifles a really good clean, but apparently not.
Brought a can of foaming cleaner after cleaning, finally back down to 2704 fps

Standard clean won’t budge carbon ring. Good you got it sorted

Originally Posted by Hunty1

Just had a similar thing.
Thought I'd sorted a load for my 7/08 with RL17 and ELD-X 150gr. Tested up to 47.5gr in new lapua brass and settled on 47gr with a COAL of 2.93", No signs of pressure (book max = 47.5gr)

Fast forward a few months. Went to the range to measure some drops to get a handle om MV and bugger me getting sticky bolt lift and extractor marks. 455yrd drop suggested MV of 2900fps!!! Way too hot!

It's been bugging me as to the cause as I'm reasonably pedantic when I load. Only thing I can think of is I used Oneshot case lube and didn't clean the cases after sizing. I wonder if the brass is still slightly lubricated and hasn't got enough friction to grip the chamber walls and is generating high bolt thrust? Be keen to hear others thoughts?

All cases where trimmed to spec
Confident charge weights were okay as checked scales regular throughout with reff weights.
Projectiles are still over 1mm away from the lands.
temperature was about 12 degrees (within 5degrees of when original load development done).

If you did your load development on virgin brass I’d expect the velocity to increase on subsequent firings as less energy is lost to fireforming the case. I got 100fps gain on second firing of Lapua brass for a 6.5 284

My .300 Win Mag increased mv by 80 fps from 2900 to 2980 with 208s over just a few rounds (chrono verified) at around 100 round count.

I clean my rifles with Autosol and a wire brush every 200 rounds, especially in the throat area. I think many shooters are too precious when cleaning their barrels and don’t get enough carbon out or polish the throat sufficiently to help slow erosion. Jags and plastic brushes are fine for normal cleaning but don’t really get into the grooves or prevent rings forming. Barrels are made from steel, not butter. That said, I use good bore guides (Lucas), Dewey rods, and don’t overdo it.

That’s my routine, but ask ten shooters and you will get ten different answers. Even barrel manufacturers don’t agree on cleaning routines.

$20 (but probably a rather long wait nowadays for freight) will put to rest any question over how much or how little to clean, and how effective your methods are on both carbon and copper. Would ID this sort of issue quick-smart.
https://www.nzhuntingandshooting.co....hawkeye-45930/

Originally Posted by Spitfire

My .300 Win Mag increased mv by 80 fps from 2900 to 2980 with 208s over just a few rounds (chrono verified) at around 100 round count.

I clean my rifles with Autosol and a wire brush every 200 rounds, especially in the throat area. I think many shooters are too precious when cleaning their barrels and don’t get enough carbon out or polish the throat sufficiently to help slow erosion. Jags and plastic brushes are fine for normal cleaning but don’t really get into the grooves or prevent rings forming. Barrels are made from steel, not butter. That said, I use good bore guides (Lucas), Dewey rods, and don’t overdo it.

That’s my routine, but ask ten shooters and you will get ten different answers. Even barrel manufacturers don’t agree on cleaning routines.

The barrel makers will love you!
Try the wipe out foaming bore cleaner,
You will be amazed, no scrubbing just let it do its work.
It gets every thing out.

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Originally Posted by jwightman

Problem solved.
I thought I gave my rifles a really good clean, but apparently not.
Brought a can of foaming cleaner after cleaning, finally back down to 2704 fps

Which cleaner preytell?


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