Velocity Increase question??

[Rflamm250]

So I recently put together a 6xc with a Defiance Tenacity action, Hawkhill barrel. Did my normal break in which consists of 25 rounds and 5 cleanings. Loaded 105 hybrids .020 off, 3 each at 39, 39.3, 39.6, 40 grains H4350. Went to 400 yards as normal for my load development. Shot 3 fouler s then Starting with the lowest charge shot for groups. Every group got tighter and tighter until I reached 40 grains which shot close to 1 inch. Cleaned barrel again fouled it and shot the same charges but this time from the 40 charge down. Groups started over 2 inches and shrunk as the charge weight lowered until I reached 39 which shot around 1 inch. So basically was opposite of first go round. Loaded 3 more at 40 grains again and shot over magspeed 3028, 3055, and 3079 velocity seemed to increase 20+ fps every shot starting with cold barrel. Has any one seen this and did the barrel ever settle?

 

[LaHunter]

Could be a couple factors involved: 1) your barrel may still be 'breaking in / settling down' until you get into the 100-150 rounds through it. 2) It could be cleaning related, especially if you don't have many rounds through it. It may be worth while to repeat your previous load testing, but without cleaning. It may be good to allow the barrel to cool between shots also along with keeping your ammunition out of the sun during your range session. I usually use a timer and allow at least 3-5 minutes between shots depending on the ambient temperature.

 

[WeiserBucks]

Definitely cleaning related and definitely new barrel related. As long as accuracy is within a reasonable range, I wouldn't be serious about fine tuning a load until you're past at least 100 rounds. After you get 100 or so down it , fire 20 to foul it and then get serious about load development. No need to clean constantly.

 

[Rflamm250]

Could be a couple factors involved: 1) your barrel may still be 'breaking in / settling down' until you get into the 100-150 rounds through it. 2) It could be cleaning related, especially if you don't have many rounds through it. It may be worth while to repeat your previous load testing, but without cleaning. It may be good to allow the barrel to cool between shots also along with keeping your ammunition out of the sun during your range session. I usually use a timer and allow at least 3-5 minutes between shots depending on the ambient temperature.

I was suspect to all the things you mentioned. Just curious if anyone has seen results similar

 

[Rflamm250]

Definitely cleaning related and definitely new barrel related. As long as accuracy is within a reasonable range, I wouldn't be serious about fine tuning a load until you're past at least 100 rounds. After you get 100 or so down it , fire 20 to foul it and then get serious about load development. No need to clean constantly.

This is exactly what I usually do, the last cleaning was at 50rnds and I wont clean again until 100. At that point will have brass fireformed and will rework a load. I have just never seen anything like it before.

 

[WeiserBucks]

I wouldn't put to much stock in the early results unless accuracy is very poor or a serious pressure problem. You're on the right track, break it in and then get serious.