At the same time I tested the pc'd bullets I also made up the same loads to test the traditionally lubed lee 160-312 bullets. Because of the tl design there isn't a lot of lbt lube that goes into the tl grooves. So I did 1 thin coat of 45/45/10 on them also.
[IMG][/IMG]
What I found about this bullet/lube combo I never expected. I always thought of bullet lube as a gasket, today sure proved it. I tested the traditional lubed bullets with the same loads I used for the pc'd bullets. 10-shot groups @ 100yds.
[IMG][/IMG]
The brass was range pick-ups/mixed nato, the bullets were not sorted for defects. Cast them and picked out any obvious flaws, no sorting. The H335 powder isn't the greatest for cast bullets. And the primers were I have no idea how old magnum large rifle primers. A pillow stuffing filler was used with all loads, lightly packed to the bottom of the neck of the case. The traditional lubed 34gr/35gr 10-shot groups were 2 1/2" outside to outside. The 36gr loads went south and the 37gr loads were all over the place.
The rifle I used was an old puma rifle I just re-barreled and bedded. This was the 1st outing with it. I did test the bbl before I bedded it the other day. It's a 30" bbl and it usually takes 1 round for every inch of bbl to season a clean bbl. This is what the muzzle looked like after 14 shots with traditionally lubed bullets.
[IMG][/IMG]
The bbl is slick, real slick with a taper at the muzzle. Shot fouling shots and 40 pc'd test loads 1st. Then more fouling shots and 40 traditional test loads. There was no leading in the bbl, it cleaned up with 2 wet patches, a couple of passes with a nylon brush and a couple dry patches.
What was surprising to me was that the lube failed but there was no leading. Both bullets had gc's installed the same way from the same batch of al (home made). There just wasn't enough lube to seal the bbl but there was enough to keep it from leading.
Results from 10-shot strings pc'd bullet and traditional lubed bullet both sized to .311" cast from the same casting session/same pot of ally/same batch (1 20# pot). All bullets got gc's installed at the same time from the same batch of home made al gc's. The pc'd bullets got pc's and then sized in a lee push thru sizer. The traditional lubed bullets got sized in a lyman 450 sizer (lbt blue) and a coat of 45/45/10 applied.
34gr of H335
pc'd bullet 2489fps lubed bullet 2464fps
sd 25.3fps sd 15.7fps
es 75fps es 50fps
35gr of H335
pc'd bullet 2550fps lubed bullet 2536fps
sd 15.1fps sd 11.7fps
es 49fps es 34fps
36gr of H335
pc'd bullet 2610fps lubed bullet 2574fps
sd 15.6fps sd 21.4fps
es 47fps es 55fps
37gr of H335
pc'd bullet 2679fps lubed bullet 2617fps
sd 11fps sd 16.6fps
es 29fps es 58fps
As you can see as the powder/pressure/load went up the traditionally lubed bullets failed. The 37gr load couldn't hold 10 shots on the paper. The was also a loss in velocity and the sd/es climbed. While the best group of the day was with the pc'd bullet/37gr combo, it did 2 1/4" outside to outside. While 2" groups are not that great I'm sure they could get tightened up a little tweaking and some actual bullet culling.
I plan on giving the bullets a 2nd/thick coat of the 45/45/10 and re-testing the 36gr and 37 gr loads.
These bullets had a gc on them, there was no leading in the bbl. But the lube failed because there just wasn't enough of it there to seal the bbl with the higher pressure loads. Figured I'd keep using H335 for awhile, faster learning curve.
Just some interesting results for the 1st time out with the new bbl.
|
   
   
|
|
Reply With Quote
