My barrel picked up speed, do I go back for accuracy?

[EXPRESS]

I was getting 2880fps with 74.5gn if VV N160 under a 225LZR in .338 win mag.

Recently I chronoed with the magnetospeed and found it was now, after putting about 250rounda through the barrel, giving 2970fps.

So today I tried 74gn and still got 2935fps.

When I did the initial load development using the OCT method I was at 2880fps, so to maintain the accuracy node, should I reduce the load untill I am back at 2880?

Next test will be on paper but I don't want to go back to square one with this.

 

[TXAoudadKlr]

Not much help but. Before hunting season I checked my zero and fired a sub 1/4 MOA group. I fired ~12 rounds during the season before I took a shot at a rock at 550 and noticed I was 1/2 minute high from original drop data. To get my drops to match up I had to up the velocity 40FPS over what the load originally chronographed at.

 

[Dgd6mm]

I was getting 2880fps with 74.5gn if VV N160 under a 225LZR in .338 win mag.

Recently I chronoed with the magnetospeed and found it was now, after putting about 250rounda through the barrel, giving 2970fps.

So today I tried 74gn and still got 2935fps.

When I did the initial load development using the OCT method I was at 2880fps, so to maintain the accuracy node, should I reduce the load untill I am back at 2880?

Next test will be on paper but I don't want to go back to square one with this.

Well how is it shooting? Are you still in the accuracy node? If not and you were happy with what you had, reduce till your back at original load speed and check for accuracy.

 

[Mike 338]

Are you using the same chronograph, same brass, same primer and same (or close) ambient temperature? Even different lots of powder can cause a pretty big swing. Maybe it's your barrel but chances are it's something else.

 

[WildRose]

If it were me I'd just shoot it as is and see if the accuracy is still there. If not then dial it back a bit and see where your new accuracy node is.

 

[FEENIX]

If it were me I'd just shoot it as is and see if the accuracy is still there. If not then dial it back a bit and see where your new accuracy node is.

+1! I'll take accuracy over velocity anytime.

 

[snookntarpon]

Mine picked up speed too after about 180 rounds. Still havent chronographed it but POI changed to zero @ 100 from 2.3"@ 100 Accuracy still the same but would like to veryfy at 200 and 300 and chrono w magnetospeed. will get to it soon.

Keep me posted on what you find.

Thanks
SnT

 

[Schnyd112]

My .260 picked up speed for the first 300ush rounds. Accuracy is still on par with my initial load development, .35-.4" at 100, it is just moving 60-65 fps faster than the first loads. Went from initial speeds of 2820avg over 10 rounds to 2880.

 

[sable tireur]

EXPRESS,

I can speak to using Bartlein, Lilja, Hart, Rock Creek and Schneider barrels with the Bartleins being the most by far. Every barrel broken in gained velocity by up to 200 FPS, obviously some not quite as much but still a noticeable gain. Yes, POI was affected as was the group size if it was relevant, much to the chagrin of the shooter, especially if they were trying to shoot in a competition...

Next test will be on paper but I don't want to go back to square one with this.

Your first step SHOULD be to shoot it on a target and get a good idea of the average accuracy. This means you need to shoot it for group size several times under similar conditions of the first test. Better yet, you should be testing under the conditions that you will be hunting in. Targets fired in hot weather will be different from targets fired in cold weather. Common sense. If this is not possible then you need to set aside some time right before hunting season to run some targets.

You don't need to start over necessarily but shooting some targets will be required.

Regards.

 

[FURMAN]

I will reiterate a couple things and add one. Barrels almost always gain speed after broken in. This typically changes the "accuracy load". Like others have stated check your accuracy and go from there. I will add that I never trust a chrono day to day. I will use them to verify extreme spreads that I see on long range ladders. I use actual drops to get my true velocities.