New Barrel speeding up ??

Gidday Guys

I'm working up a 6mm Crudmoor just now - with a new Hardy barrel. I shot it today with Sierra 110's and it ran real slow with loads that have a known performance in chambers cut with the same reamer - like about 150 fps slow.

The thing that's really got me beat I is tried a few rounds to get it on paper with some 85's I had, and they shot "fast" and with mild pressure signs with a moderate load.

Do barrels speed up much as they break in ?? How many rounds is it likely to take??

And yes, the chrony was used by another shooter who obtained "predicted" results

I am not sure if it's as the break in but maybe as they warm up. I loaded up some 55 gr Noslar BT's in my 243 and tried them yesterday. The velocity went from 3333fps, 3363, then 3385 fps.( mild load)
I noticed this with my 6.5 x55 when shooting at the TePuke Rifle Club the recorded velocities increased as the barrel heated up.

I've read up to 200 plus rounds is required to smooth the irregularity from the manufacting of the barrel. Dependant on maker. So yep they speed up.

Barrel speed varies from rifle to rifle with the same load. Chamber dimensions, headspace, width of lands, bore diameter, twist rate, temperature, bullet hardness, etc. are all variables that are never identical, even with identical model rifles with consecutive serial numbers. Numbers on a chronograph are just that-numbers. What is important is down range performance.

you said you got higher than expected speed with the 85s.....maybe the make/type of projectile is answer to your riddle....eg speer Vs hornady
there are awesome 85-90grn 6mm projectiles out there that folks have been slaying critters with for years....and plenty of 100grn ones for deer too,110 is heavy for calibre so speed is always going to be subject to all ducks in row..... keep us posted on results,this has me intrigued .

Friend of mine has a hardy barrel and is slow compared to my truflite both 6mm,
Ive got 100fps on him with same load


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So . . . I tried a different newer can of AR2209 I had. Velocities are a lot closer to what they should be, still a tiny bit slower than what various predictive tools show, but "within cooey". I hadn't used the can of H4350 in question for a couple of years and my notes don't offer any clues that I found it "slow" so its probably gonna remain a mystery

so what powder had you used with the 85s?????

AR 2208, should have thought about the whole thing a bit more eh??

My hardy barrel was ok with 110's in the same cartridge, Did they cut the chamber?

If so I can share my data.

All my barrels speed up about 80-100 after 150-300 rounds.

@Cowboy06 has a lot of experience loading. he might be able to help.

@gundoc is the most talented riflesmiths I know.... what he said is bang on.