When do you see a barrel stop speeding up?

[bsumoba]

I have seen my barrels almost all start out slow and then pick up and stabilize after a certain point.

At what round count do you normally start to see the barrel picking up and then stabilize?

 

[noload]

First off I'll say I do not crony a lot, only during the load developing, which would be in the first 100-300 rounds. I would say after that if your barrel gets faster its because of the condition of fouling going on. I say that because after I clean good and shoot at a 300yd target the first round will always hit about 1" low, the second round will hit about 1.5" higher than that. Then the 3rd, 4th,5th ect. will settle in, and group between the 1st and second hits, It may climb slightly throughout a sting of 20 (may be 1/4 ").
I did have 1 krieger 6br that seamed to get faster till it had over 1000 rds in it. I judged this because of the scope elevation setting and I kept having to go down on the turret setting till it had over a 1000 rds, though the rounds were all the same charge wise and seating depth.(I keep a record of my scope setting every time I shoot so I just wondered why saw this happen) This may also have been caused by finding a good accurate load in the cool spring time and continuing to shoot it into the heat of the summer without changing it for the heat factor. To answer your question.. I guess every barrel is different.

 

[Milo 2.0]

To answer your question.. I guess every barrel is different.

^^^So true.
For years I shot Krieger and Brux barrels, just like clockwork at rd 70 I would get about a 70fps jump in speed. Then I started messing with Mullerworks, Rock Creek, which the Rocks never did speed up.
My last one, a Hawk Hill was a total wreck as far as load development for me, but starting at rd 95 up to rd 115 it gained considerable speed and everything came together for me.
It's a crap shoot.

 

[expiper]

OP,,,I pay more attention to how the shoots on the target ,,,bbs and time are too expensiv/valuable to sit and shoot them thru a chronograph,,,once I get initialy load development done (very little chrono time) I just keep an eye on pressure and try to clean the bbl as often as possible during the event,,,velocity will change from hour to hour with temp as the day wears on,,,,so what a bbl does months or years later after 300 or 400 rounds is of no importance,,,I will put 500 rounds thr a bbl at a national event ,,no time to chronograph there,,,,Roger

 

[bsumoba]

The reason I ask is because my current barrel seemed to never change and I have 340 rounds down it. my concern is seeing a speed change a little bit later on and at the worst time....during a big match. I feel like 340 rounds should be plenty.

I have another rifle that is shooting excellent right off the bat and needed no load development. I am just shooting the same load as my other gun which makes it REALLY nice. it just worked out that way. ;D the speed in the new gun is about 20 fps slower than the other gyn and it's got just north of 150 rounds now I think.

I don't do a whOle lot of chronographing and when I do, it's mainly at the end of load development when I have an accurate load. I will sometimes shoot 1 or 2 shots during my ladder just to get an idea of the speed, but after that, I don't take out the magneto until load development is complete.

 

[lloydx2]

I think sometimes its the amount of taper that's lapped into the bore.
During break-in I see more copper fouling in the last 2 inches of the muzzle
than anywhere else.

Lloyd

 

[noload]

I check barrel bore ID with a cleaning rod and the snuggest pilot bushing in my set, and I have not seen any taper to speak of from breach to muzzle. I can not explain why I get more copper at muzzle end also.

 

[RDavies]

I would say that around 80% of the barrels I have used have sped up to some degree and it is usually within 100-200 rounds that it starts, then speeds up quickly over 50 shots or so, then stabilizes by around 150-250 shots. I have heard of some others (not many) which kept on speeding up until around the 400 round mark. I often get barrels rechambered if they are good ones and previously used barrels which have been rechambered never seem to go through the speed up, only totally new barrels.

 

[100FUEGOS]

My experience with the 7 SAUM has been a path of sin. The first shots looked for the maximum load and I reached 59 grains of RS70 and found at 2950 fps the hard bolt. I went down to 2890 and got a good result ... I went to a competition with 200 shots. And half of the competition notice the hard pin in the last shots, something more than 300 ... And notice that the precision also changed.
Back home, I take measurements and I see that the load of 57.2 of RS70 no longer had the 2890, had risen to 3000 fps. And the super hard pin. I had to download 3 grains to recover the 2890 node.
I use a polygonal gun sabatti ...
Thank you.

 

[mike a]

The reason I ask is because my current barrel seemed to never change and I have 340 rounds down it. my concern is seeing a speed change a little bit later on and at the worst time....during a big match. I feel like 340 rounds should be plenty.

I have another rifle that is shooting excellent right off the bat and needed no load development. I am just shooting the same load as my other gun which makes it REALLY nice. it just worked out that way. ;D the speed in the new gun is about 20 fps slower than the other gyn and it's got just north of 150 rounds now I think.

I don't do a whOle lot of chronographing and when I do, it's mainly at the end of load development when I have an accurate load. I will sometimes shoot 1 or 2 shots during my ladder just to get an idea of the speed, but after that, I don't take out the magneto until load development is complete.

Aside from a chronograph what tool could you have that would tell you exactly when or if it's going to speed up? Maybe you can buy a borescope and have two tools to frustrate you. I say save your money, buy more bullets and watch you target. Cheer Mike

 

[mikegaiz]

Aside from a chronograph what tool could you have that would tell you exactly when or if it's going to speed up? Maybe you can buy a borescope and have two tools to frustrate you. I say save your money, buy more bullets and watch you target. Cheer Mike

Do not buy a bore scope!!!!!! It will ruin your life. You can never go back........

 

[spife7980]

I wanted to answer it for myself so I chronoed every one of the first 100 shots through my 6xc criterion barrel. The average maybe was 15 fps increase only but that was well within the extreme spread of the shots.

So a pretty pointless exercise in my case. I will still do a crude ladder right away just to make sure Im not loading the forming rounds in a scatter node but I will form 100 rounds of brass in the barrel to break it in with and then start actual development from there.

 

[Boatschool02]

Labradar #s for my 6mm 7.83T Brux during fire forming.
First new barrel with the LabRadar so I can't compare to previous calibers or manufacturers.
Velocity increased another 35-45 fps over the course of the next 100 shots.
I'd say it was "mostly" stable after 150.

 

[comagutsa]

My last 2 barrels were about 120 to 150

 

[swd]

My last few have been in the 100-150 range. Usually during a match, but I knew it was coming.