Been a while since I chrony my load as I haven't shot the rifle in a few years. Had to add a 3.5 grains more power to get back to the velocity i once had in my notes. No idea of the round count but getting up there. Bore is definitely rough but holds 1/2-3/4 moa at 100. I have paper at 100, steel at 358yrds, 411 yrds and 583yrds. At the 2 shorter steel ranges the bullets hit there they should according to the applied ballistics, at 583 it is shooting 3 1/2 moa low. I'm shooting the 55g sierra sbt, what are your thoughts on the drastic drop? Bore shedding the jacket causing a drop in bc? I haven't experienced this before.
22-250ai bc question
- Thread starter mikea5232
- Start date
old_heli_logger
Gold $$ Contributor
My guess would be negative compensation
What’s that?
old_heli_logger
Gold $$ Contributor
The opposite of Positive Compensation. Positive Compensation is when slower bullets impact higher than faster bullets. This is due to your barrel bending up or recoil as your bullet exits. The slower bullets stays in the barrel longer... here's a video that explains it better
Good luck
Mike -
Howdy !
Bullet impact point wise…. did you happen to re-stock the gun, or change scope mounted height; in the intervening years you mentioned ?
Am asking about that independent of the change in powder charge you mentioned.
With regards,
357Mag
After adjusting the load to get velocity back up. I put a thermal scope on it with ballistic on it. When i could not hit the plate at 580yrds i took the thermal off and put the day scope back on. Checked zero and dialed to 580 from the applied ballistics app and still shot low. Dialed up and up till I could it the plate. The wind was blowing pretty good yesterday,90 degrees cross wind so the hits on the plate were wide and had 1/2moa vertical. I'm not a good wind reader....
Same bullets as before? Or a new batch? They could have changed a little. Same lot of powder? That much time in the safe with my Ruger 22-250 would mean the stock had moved (wood stock?). 580 is not a chip shot lots of atmospheric conditions could be in play. 357 mentioned scope height, that is a good thing to look at. Rough bore and damage to jacket is a real thing also. Logger mentioned negative compensation, if it is back to previous speed, and the chrono is the same as before, it should impact the same as before. But that is a whole lot of ifs. I have had chronos go crazy with batteries near death. Wish I was smart enough to be any real help.
Same 55s, probably different lot of powder. The old loaded ammo from 2019 was shooting 350fps slower than what was on the box. I had a lab radar then. Now using Garmin. Greyboe composite stock. Sight hight has been measured and adjusted for. I shoot regularly at 580. That's the furthest I can get to off my deck without setting up steel in the neighbors field.
Orr89rocz
Silver $$ Contributor
If 411 hit true and 580 is low, and sight height is correct, and your scope is tracking close to true, try creating a custom bc table to adjust for the additional drop at the velocity range its going thru between 400-500 yards. I’ve had good adjustments to 565 yrds before but had some way off beyond that that I had to customize my bc values with velocity
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