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Post by edge on Jul 15, 2005 21:56:43 GMT -5
I had time to machine only 5 rifled sabots and 2 inner sabots. The bullet that I hope to use in this barrel is the 8mm Sierra 150 grain ( shown later ). I got to the range a little late, but it was empty ( a rarity ), so I decided to only test the sabots and to chronograph a few loads. 72 grains of H4198 with a 150 grain 8mm bullet yielded 2661 fps 75 grains of H4198 with a 150 grain 8mm bullet yielded 2722 fps 75 grains of H4198 with a 250 grain SST bullet yielded 2709 fps I'm thinking that the 150 grain bullets need a slightly faster powder since the loads are so inefficient ( any suggestions ). I want to use the slowest powder that will yield a greater velocity. The 3 shots in this picture were using 72 grains 4198, a rifled sabot with a 28 Ga. wad.   Sectional Density: .205 Ballistic Coefficient: .336 above 2600 fps .329 from 2600 to 2000 fps .314 below 2000 fps Notes: Flat base Jacketed soft point. |
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Post by bwaddy on Jul 16, 2005 1:38:41 GMT -5
What about straight N110 or a duplex N110/H4198?
Bret
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Post by RBinAR on Jul 16, 2005 4:03:45 GMT -5
8-)Try either N120 or Imr-4198 both will exceed the speed of H4198 for the same charge.
Pack Imr-4198 very tightly
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Post by edge on Jul 16, 2005 6:52:55 GMT -5
Thanks for the input guys  Any suggested powder weights? For a slight clarification on sabot/bullet weights: 250 SST + Sabot weighs 262 grains; 150 grain 8mm + Inner + outer Sabot weighs 185 grains; 150 grain 8mm + rifled Sabot + 28 Ga. base cup weighs 192 grains. Thanks, edge. |
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Post by dave d. on Jul 16, 2005 10:49:52 GMT -5
:)edge, i would have to agree with the duplex thing how about 10/70 of 110/120 or 80grs straight of n120 and see what that get's in velocity.these loads with a 200sst gave me 2830fps and 2800fps respectively.
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Post by DannoBoone on Jul 16, 2005 22:29:27 GMT -5
:)edge, i would have to agree with the duplex thing how about 10/70 of 110/120 or 80grs straight of n120 and see what that get's in velocity.these loads with a 200sst gave me 2830fps and 2800fps respectively. How were those loads as far as accuracy? WW's? Etc.? |
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Post by dave d. on Jul 17, 2005 12:38:54 GMT -5
[
How were those loads as far as accuracy? WW's? Etc.?
[/quote]
:)danno,both did 1 1/2" or better with the washer sabot and ww @ 100yrds.i now belong to a 300yrd range and will be able to check accuracy out further but i will no longer have a .50 because i'm waiting on my .45 pac-nor conversion so all 300yrd shooting will be with the .45.
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Post by edge on Jul 17, 2005 15:53:41 GMT -5
Thanks, I have only used N120 in my 45. How much of a difference is there in burning speed between N120 and H4198?? I have a program that estimates my pressure at 37,000 for the 250SST @ 2709 fps, and right at 30,000 for the 150 grain bullet ( + 40 gr. sabot ) @ 2722 fps. It certainly seems as though I would be better served by a tad more pressure with the lightweight bullet, especially when the weather cools. Thanks, edge. :)edge, i would have to agree with the duplex thing how about 10/70 of 110/120 or 80grs straight of n120 and see what that get's in velocity.these loads with a 200sst gave me 2830fps and 2800fps respectively. |
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Post by dave d. on Jul 17, 2005 16:55:12 GMT -5
:)edge,i would say that n120 is about 75 to 100fps faster then h-4198.just going by what i've shot a 65gr charge of n120 yielded the same velocity as a 70gr charge of h-4198 with the same componets.
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Post by edge on Jul 17, 2005 17:01:52 GMT -5
Thanks, I'll give it a try edge. Dave, that was in the 50 cal, correct? :)edge,i would say that n120 is about 75 to 100fps faster then h-4198.just going by what i've shot a 65gr charge of n120 yielded the same velocity as a 70gr charge of h-4198 with the same componets. |
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Post by dave d. on Jul 17, 2005 17:07:18 GMT -5
:)edge that's correct it was in the .50.goodluck with your little project.
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