Here is a reposting from Calguns of my three-part report of some initial work with light bullets. That report was divided into three posts, which I'll do here also.
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185-grain Trials, Part 1
I began my 450b reloading trials for the 1903 Springfield (see my 15 May post) with the Hornady FTX 250 gr bullet with Lil'Gun, and worked up to the maximum loads listed by Hornady without incident. My next project was to try lighter bullets at higher velocities.
There was some concern in posts above that my barrel's faster-than-factory 1:16 twist would overspin and perhaps destroy light bullets, so I picked the Hornady #45137 .451 185-gr FMJ SWC encapsulated for initial trials. It is advertised as having a stronger than normal jacket, which seemed appropriate for this application.
I used new Hornady cases, Lil'Gun powder, and CCI BR-4 primers for my first trial series. Cases went through the Hornady FL sizer and expander dies before loading, altho they probably didn't need the sizer. The initial series used loads of 38-42 grains, in 1 grain increments, with two cartridges for each load. The bullets were seated to an overall length of 2.040 inches. The crimp in the seater die wasn't used, but I did use the taper crimp die. The cartridges readily passed the "thunk" test that has been described in earlier posts.
My PACT chronograph uses a 2-foot screen spacing, and the midpoint of the screens was 8 feet from the muzzle.
The chrono readings averaged for two shots per powder weight, were:
38: __ 2512 fps
39: __ 2501 fps
40: __ 2664 fps
41: __ 2701 fps
42: __ 2765 fps
All the cases extracted easily. The case diameters measured immediately in front of the extractor groove showed no measurable expansion. The primers showed no pressure signs, and the case heads were unmarked with extractor grooves, etc.
The bolt gun is pretty light at a smidgen over 7 pounds, so its recoil with the 185 gr bullet at better than 2750 gets attention; 185 at 2750 is more energy than the 180-grain 30-06 factory.
Based on the lack of pressure, I decided to load a similar series with greater weights of powder. See my next post.
Here's a photo of the loaded 185-grain FMJ SWC. (The camera was tilted but the cartridges will appear ok if you just tip your head a bit.)