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Brass variations? (Read 3308 times)

BM1455 KCA Forum Member Offline Krag Enthusiast! Posts: 52 Joined: Mar 1^st, 2013	Brass variations? Nov 7^th, 2016 at 9:12pm	Print Post
	For you guys who have had experience loading Hornady 220RN and IMR 4350 with various brass cases. What have you noticed about using different cases with a given load? I am working my way up from 38 grs of IMR 4350 using Remington cases. I was in the +/-1800 ft/ sec @ 38 grs. At 39 grs I was getting more like 1915 ft/ sec. I came up with a variety of Winchester cases and some relatively recent, others older, and some even older 1950's Winchester super speed cases. They weigh more than the Remingtons do. In general, how different are your loads? Also, given that I am around 1915 ft/ sec @ 19 grs of IMR 4350, will 40 grs and being a little over 2000 ft/ sec be any issue? (Model 1898 with a very nice full length barrel) Thanks.


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Parashooter KCA Forum Member Offline Kragmudgeon Posts: 514 Location: Connecticut Joined: Feb 4^th, 2010	Re: Brass variations? Reply #1 - Nov 7^th, 2016 at 11:41pm	Print Post
	To quote from NRA's "Handloading" book, "A satisfactory rule of thumb is to decrease the charge weight in the heavier cases by 12 percent of the difference in case weights." Doing so should ensure that pressure in the heavier cases is not greater than was experienced in the lighter cases with the original charge, although velocity may differ. A somewhat more scientific approach is adjusting the charge to maintain the same chronographed velocity. Resulting pressure should be close enough for safety unless there's an abnormally large difference in case weights (more than ~20%).


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psteinmayer KCA Forum Member Offline Krag Enthusiast! Posts: 2391 Location: Ypsilanti, Michgan Joined: Aug 30^th, 2011 Gender:	Re: Brass variations? Reply #2 - Nov 8^th, 2016 at 12:17pm	Print Post
	To be honest... I never worried about it (although as a match shooter, I probably should). I always load 40.0 grains of 4350 in every case... both Remington and Winchester. I do weigh every charge though to ensure it is exactly 40.0 grains. I do fairly well with it!


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BM1455 KCA Forum Member Offline Krag Enthusiast! Posts: 52 Joined: Mar 1^st, 2013	Re: Brass variations? Reply #3 - Nov 8^th, 2016 at 7:49pm	Print Post
	psteinmayer wrote on Nov 8^th, 2016 at 12:17pm: To be honest... I never worried about it (although as a match shooter, I probably should). I always load 40.0 grains of 4350 in every case... both Remington and Winchester. I do weigh every charge though to ensure it is exactly 40.0 grains. I do fairly well with it! I always measure each load as well. I have worked my load up using the recent Remington brass. I am at 39 grains of IMR 4350 now and I am in the low 1900 ft/ sec already. (1910-1935) That is a little over 100 ft/ sec faster than my first loads which were loaded to 38 grains of that powder. So, a little over 100 ft/ sec more velocity with one full grain of powder. Is this way off or about right with these rifles and complainants? My question is that since I am already up to an average of about 1920 ft/ sec at 39 grains of 4350 maybe 40 will put me a little bit high? (My rifle is in spec and has an excellent original barrel.) Thoughts? Correction: I mistyped my my original loading. It should read 38 Grains, not 37 grains. I have corrected it in the text. So it was about a 100 ft/ sec increase as I stated above.
	« Last Edit: Nov 9^th, 2016 at 2:50pm by BM1455 »

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Parashooter KCA Forum Member Offline Kragmudgeon Posts: 514 Location: Connecticut Joined: Feb 4^th, 2010	Re: Brass variations? Reply #4 - Nov 9^th, 2016 at 12:56am	Print Post
	BM1455 wrote on Nov 8^th, 2016 at 7:49pm: . . .I am at 39 grains of IMR 4350 now and I am in the low 1900 ft/ sec already. (1910-1935) That is a little over 100 ft/ sec faster than my first loads which were loaded to 37 grains of that powder. So, a little over 100 ft/ sec more velocity with one full grain of powder. . . If you gained ~100fps from 37 to 39 grains, that's ~50fps per grain, not 100. ~50fps per grain is what QuickLOAD software predicts - Cartridge : .30-40 Krag Bullet : .308, 220, Sierra SPRN 2180 Cartridge O.A.L. L6: 3.089 inch or 78.46 mm Barrel Length : 30.0 inch or 762.0 mm Powder : IMR 4350 Predicted data by increasing and decreasing the given charge, incremented in steps of 2.564% of nominal charge. CAUTION: Figures exceed maximum and minimum recommended loads ! Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time % % Grains fps ft.lbs psi psi % ms -07.7 84 36.00 1989 1932 28566 4750 87.8 2.033 -05.1 87 37.00 2041 2035 30619 4916 89.1 1.974 -02.6 89 38.00 2093 2141 32819 5077 90.3 1.917 +00.0 92 39.00 2146 2249 35180 5233 91.5 1.862 +02.6 94 40.00 2198 2360 37718 5383 92.6 1.807 +05.1 96 41.00 2251 2474 40443 5528 93.6 1.752 ! Near Maximum ! +07.7 99 42.00 2303 2591 43377 5666 94.5 1.699 ! Near Maximum !


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BM1455 KCA Forum Member Offline Krag Enthusiast! Posts: 52 Joined: Mar 1^st, 2013	Re: Brass variations? Reply #5 - Nov 9^th, 2016 at 2:50pm	Print Post
	I made a correction to my post. It was about a 100 ft/ sec increase. I think I fat fingered the original load. It was 38 grains, which was increased to 39 grains with my second batch of loads, which produced about a 100 ft/ sec increase. So, Since the group was reasonably good but just a little bit low I will probably just adjust my rear sights a little bit and call it good at 39.


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