Post #1
This thread is a report of some initial trials with lightweight 160-grain bullets trying to obtain high velocities in the 450 Bushmaster.
(Standard Warning: For the work described below I used my bolt rifle, which has a 1:16" twist barrel with 0.451" grooves. I don't worry about pressures for reliable semi-auto operation. If you try to duplicate what I did using different rifles, different components or different techniques, bad things may happen. Be careful. Don't forget that this information is coming to you via the internet.)
After I made my first post in mid-May 09 on the calguns.com 450B thread, our fearless Wildcatter pointed out the possibility of working up to some pretty giddy high velocities with the bolt gun. He specifically mentioned 3000+ fps. I was interested, and started to look for light-weight bullets that might be up to the job, since lighter bullets generally go faster than heavier.
The lightest weight bullet I could easily find in catalogs was the 160-grain Barnes bullet manufactured for the 45 GAP. It was a bit pricey for a lot of trial-and-error exploratory work. I spent my initial efforts with the 185-grain Hornady fully encapsulated SWC instead. My intent always was to use the 160-grain Barnes bullets after learning enough to try them without wasting a lot of them.
I finally obtained 3000+ fps with the 185s and reported it here in May this year. LINK. The load was a compressed charge of Lil'Gun with a heavy crimp. Accuracy was about 5 moa.
After breaking the 3000-fps barrier, I decided I was ready to try the 160-grain Barnes bullets. Here's an image of that bullet linked from Midway's web site:
These are made with a fearsome-looking hollow point that is really deep. Measured dimensions on the lot of these bullets that I purchased: Length = 0.6655 +/- 0.0005"; Diameter= 0.4500" +/- 0.0001". The depth of the hollow point was about 0.40", or 60 percent of the bullet length.
I've attached some photos I made of the bullets.
edited to update link to Midway image - June 2013