Home Forums Reloading Reloading Software OBT

Just started using QL with the OBT tables and see that my Tikka is a 22 7/16" length barrel. Does anyone know if you can simply divide the difference between 22 and 23 to come up with an OBT for a barrel in between the two?

Also, is there a need to compensate for a muzzle break? It clearly isn't the same as an unperforated barrel but how much differnce does it make in the OBT calculations?

thanks!

Well, I found one answer - here is a link to a calculator that Chris Long built for getting OBT for any barrel length.
http://www.the-long-family.com/optimal%20barrel%20time.htm

Still wondering if anyone knows what effect a muzzle brake has on the OBT.

Got the second answer from Chris Long himself. He was kind enough to reply to an email. Says a lot about him -- can't say enough good things about someone willing to do all the work he has done on Optimum Barrel Time and then to just give to anyone who wants it. OUTSTANDING!!

Anyway here's his answer to the question of Muzzle Brakes - "I have found that the brake does nothing to the shock wave, hence, the OBT times are the same with and without. The threads simply do not allow much if any of the shock wave into the brake, so the reflection is still at the muzzle end of the barrel. However, the brake WILL affect the bending modes, and your POI will most probably shift. I have tried three different rifles, both with and without brake, and the group size stayed essentially the same.

Just use the bolt face to crown dimension when looking up the OBTs.

Hope that this helps!

Cheers,
Chris "


I have had a really wonderful time talking to myself on the internet!! I find myself very interesting to listen to.

CRounds,

I enjoyed your post & both your responses!

I am new to Quickload-2 weeks!- and I'm still trying to wrap my dessicated brain around Chris Long's OBT theorem.

Sadly enough,I'm still too dense to contribute.

But I like your thread!

----AttitudeRN