Thread: GRT Optimal barrel time calculation

Anyone used the OBT Calculation and achieved a noticeable improvement in group size?
Or is it just woowoo (like a lot of reloading methods/ theories seem to be lol)

The problem with trying to decide whether or not it makes a difference, like with most other load development methodologies, is sample size.

I used to use it. I'd shoot a 5rd group to get some velocity data. Then tune the GRT model and see what the OBT tool said to try.

I'd go shoot that. Probably a 5rd group. and if it didn't suck, call my load development done.

But there's just not enough data there to say whether or not it is measurably better or worse than any other charge weight I could have tried.

The science behind it is highly questionable and unproven.

Originally Posted by Pommy

The problem with trying to decide whether or not it makes a difference, like with most other load development methodologies, is sample size.

I used to use it. I'd shoot a 5rd group to get some velocity data. Then tune the GRT model and see what the OBT tool said to try.

I'd go shoot that. Probably a 5rd group. and if it didn't suck, call my load development done.

But there's just not enough data there to say whether or not it is measurably better or worse than any other charge weight I could have tried.

The science behind it is highly questionable and unproven.

Mirrors my experience exactly.