Chronographing New Barrel

[Religious Shooter]

I have a new barrel. I'm probably going to put 50-100 rds through it and then chrono.

As the barrel wears will the difference in velocity from the above reading (new barrel) be considerably different? To the point were I don't make major?

It's a .40 S&W, using 200 grain jacketed, mixed cases, FSR/WSR and Titegroup. I'm aiming for 170 PF.

Thx.

[Flatland Shooter]

I have a new barrel. I'm probably going to put 50-100 rds through it and then chrono.

As the barrel wears will the difference in velocity from the above reading (new barrel) be considerably different? To the point were I don't make major?

It's a .40 S&W, using 200 grain jacketed, mixed cases, FSR/WSR and Titegroup. I'm aiming for 170 PF.

Thx.

As long as your shells are consistant, (SD less than 15 or so) the 170 PF should be safe for quite a while.

With all other factors being equal the velocity with identical ammo will decrease as the barrel wears. But other factors over the life of the barrel will have much more effect on the velocity. That next batch of powder you purchase will probably be from a different lot and that may or may not affect velocity.

My 9x21 Nowlin barrel has in excess of 70,000 rds through it. Accuracy is beginning to suffer, but the amount of powder needed to make major has increased very little.

Bill

[.40AET]

Do yourself a favor. When you load up 300 for the first major match, make an extra 100 and keep them. Every once in a while I pop 5 across the chrono to see what they look like. After 2+ years of shooting open, the bullets that made 169.5PF at A8 in 2006, still make 169.5PF on my chrono. If I get some wierdo readings, I just pull out that load and check a couple to see where I am. It gives you a nice baseline.

[G-ManBart]

Do yourself a favor. When you load up 300 for the first major match, make an extra 100 and keep them. Every once in a while I pop 5 across the chrono to see what they look like. After 2+ years of shooting open, the bullets that made 169.5PF at A8 in 2006, still make 169.5PF on my chrono. If I get some wierdo readings, I just pull out that load and check a couple to see where I am. It gives you a nice baseline.

That's a really good idea. Sadly, I hadn't thought of that and yesterday I finished up the last two hundred rounds I had from Area-2....doh! I backed off that load a touch, but it would have still been a good baseline to have handy. R,

[Flatland Shooter]

Do yourself a favor. When you load up 300 for the first major match, make an extra 100 and keep them. Every once in a while I pop 5 across the chrono to see what they look like. After 2+ years of shooting open, the bullets that made 169.5PF at A8 in 2006, still make 169.5PF on my chrono. If I get some wierdo readings, I just pull out that load and check a couple to see where I am. It gives you a nice baseline.

That's a really good idea. Sadly, I hadn't thought of that and yesterday I finished up the last two hundred rounds I had from Area-2....doh! I backed off that load a touch, but it would have still been a good baseline to have handy. R,

Even though they do not make major, I bought 5 boxes of Winchester White Box 9mm Luger at the same time. These shells are used to give me a baseline for both my 9 Major open gun, my 9x19 production gun, and my Chrony chronograph. When working up loads, the first round or three across the Chrony are these base loads. I know what the velocity should be, and if its different I go looking for the reason.

Bill