H4350 Match Loads |
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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Posted: February 02 2020 at 10:39am |
It’s been a while since I tried a different powder for match loads. For the last 20 years, I’ve primarily used Re 15 and Varget. I’ve had good results with these powders, but decided it’s time to try something else.
Hodgdon recommended maximum load of H4350 is 48.0 grains (Remington case, 174 gr SIE HPBT and Federal 210 primer. In a 24 inch barrel, the reported velocity is 2517 fps, 41,900 CUP). My test loads are: Case: DAC 1956 (Canadian Dominion Arsenal Mk 7 Service) Primer: WLR Powder: 46.0 gr H4350 Bullet: Sierra MatchKing 174 gr HPBT .311 dia. COL: 3.07 in. 46 grains fills the case to just above the shoulder, so there is light compression of the powder when seating the bullet. After 20 years of seeing some airspace, this made me a bit nervous. But, I’ve backed off 2 grains from published maximums. The powder metered quite well thru my Redding measure, charges varied by +/- 0.1 grains from the 46.0 gr target weight as thrown from the measure. I’ll post the results after the next trip to the range (should be Friday) |
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Shamu
Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 17603 |
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Did you try vibrating the case to settle the powder, or a drop tube? Usually high density (safe) loads are good I actually aim for 85~95% full.
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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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Tapping the case on the bench settled the powder down to give 100% density. Seating the bullet easily compresses the powder.
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Long branch
Senior Member Joined: January 08 2014 Location: Georgia, USA Status: Offline Points: 251 |
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4350 is an extremely slow powder. I doubt you could even fit enough of it in the case to cause an unsafe pressure. Palma shooters use it in .308 for shooting 1000yards. They just cram all the 4350 they can fit in the case, and that's their match load.
I'm curious as to how it will do.
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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RANGE REPORT
I tested this load yesterday. Four groups of 10 rounds each fired from the prone position with sling at 200 yards. I first shot 2 groups with my standard match load of 40 gr. Varget as a control and to foul the barrel (the barrel had been completely cleaned of all fouling with Boretech Eliminator and Kroil prior to this shoot). The MPI of this load had the same elevation but about one minute left of my Varget match load. I was plagued with case head cracking and had three heads separate which caused fliers each time. In the 40 rounds fired, 10 cases had severe cracking and three separated. The first group was best, 5 inch center to center at 200 yards (2.5 MOA). I forgot to take a photo of the target, but here is a pic of my scorebook page. 8/10 rounds at 2 MOA. The second group had one case head separate giving a vertical flier. The first six shots grouped very tight, 2.5 inches vertical and less than 1.0 inch lateral spread (1.25 x 0.5 MOA). The third group had one case head separate and the fourth group Came in at 3.3 MOA. Overall, I think the load has some promise. Despite the elevation MPI being the same as my match load, recoil felt stiffer. I’m going to drop the charge by one grain and test with neck sized cases. I’ve never had this degree of case head cracking before. I’m not sure what went wrong, but the FL sizing likely had something to do with it. I’ll take some measurements of the FL sized case and compare to the fired case. |
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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I did some measurements of the brass cases as fired from the rifle and after sizing in my RCBS FL die. I have the die backed out almost 0.1 inches from the she!! holder such that the shoulder is pushed back by only 0.003 inches and the sized case freely chambers in the rifle.
The body of the case is not sized at all from the head to about 0.5 inches above the rim (max diameter reads the same after sizing, 0.454). The body of the case is reduced in diameter by 0.012 inches at the bottom of the shoulder after sizing to 0.394 inches. So, I really can't explain why I had so many case heads crack after FL sizing. It might be that the case with a reduced body diameter will first shorten as it expands to fill the chamber and then when the it grips the chamber it subsequently stretches in the web area. Just a theory...
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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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What kind of burn rate dies this new powder have compared to the stuff you were using? Is it faster or slower?
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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Goosic, H4350 is slower than Varget. Varget is about equivalent to IMR 4064.
I've never had this high a rate of case head cracking before from FL sized cases. The "o" ring method might help in this case, even thou the headspace is quite good on my No. 4 (bolt does not close on a 0.070 headspace gage). The rims on the cases measure 0.061 thickness. I'm going to load up some of these FL sized cases with my regular match load of 40 gr Varget and see what happens. |
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Zed
Special Member Donating Member Joined: May 01 2012 Location: France Status: Offline Points: 5585 |
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It could be just metal fatigue if you've reloaded the cases multiple times.
Do you anneal the neck of the cases occasionally? It does help reset the work-hardened brass. |
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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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Varget is in line with IMR4320 which is supposedly the equivalent to factory 303 loads. IMR4064 is in line with Norma 202,both of which have a faster burn rate then the Varget an IMR4320. My theory is that the H4350 is causing excessive pressure and not being released sooner as with the Varget due to the excessively slower burn rate the other powders mentioned above...
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britrifles
Senior Member Joined: February 03 2018 Location: Atlanta, GA Status: Offline Points: 6539 |
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Zed, yes, these cases have been reloaded many times. I typically cull maybe 2 or 3 out of 100 when I inspect for indications of web thinning before I neck size, I rarely see an actual crack forming. This time, out of 40 cases almost half of them cracked, some almost thru, and 3 were actual separations. I have not annealed the cases, annealing should not affect the head and web area (it's dangerous to anneal that area of the case, it will weaken the brass).
Goosic, the peak pressure should be mild as compared to my 40 gr Varget load according to Hodgdon's data. If this was an autoloading rifle, the slow powder could well be a problem when extraction is started before the case has released it's grip on the chamber. I keep thinking the reduced body diameter may have something to do with this... It's been a while since I've FL sized this lot of brass, and perhaps the rest of it will crack even with my Varget load, time will tell here shortly.
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