The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Rifles Big Bores Interesting .378 velocity resultsGo | New | Find | Notify | Tools | Reply | |
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Well, I recently acquired a Brevex actioned .378 with a 25" barrel. Having heard the legends of the "vicious" recoil, I decided to be cautious on my first trip to the range, and backed a 300 grain Hornaday soft point with 102 grains of XMR 3100, which should give a velocity of roughly 2700 fps, per the current Lyman manual. Well, much to my surprise, the rifle didn't kick all that much. When I chrono'd the load, I found that I was only getting about 2560 fps, considerably less than expected. Now the manual did indicate a "solid", which I would expect to be a Hornady, but 140 fps low was certainly unexpected. So, my question was this: was this just a slow load, or was this a slow barrel? I loaded up the following loads, all of which are supposed to generate 2900 fps, with Hornady 270 grain bullets, per the Hornady manual: H4895 91.2 IMR4350 102.1 H4831SC 106.2 H450 106.3 Now all of these loads are supposed to generate the identical velocity. The actual readings were: H4895 2969 3005 IMR4350 3030 3086 H4831SC 2898 2879 H450 3122 3144 (with sticky bolt lift both times) The H4895 averaged nearly 100 fps high. The IMR4350 averaged nearly 150 fps high. The H4831SC was nearly dead on. The H450 was about 230 fps high, and was clearly over max, judged by bolt lift. The lesson is that you clearly have no idea what's going on until you chronograph a load. The entry in the manual is no more than a swag. In my case, I'm obviously going to pursue loads with the H4831SC as that nearly exactly matched the expected readings, and is, therefore, most likely to produce predictable results. Mandatory disclaimer: anyone who uses these loads without cross referencing them is a fool. My custom rifle is not a Mark V, and is thus likely to produce unique pressure results. analog_peninsula ----------------------- It takes character to withstand the rigors of indolence. | ||
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| One of Us |
Thanks for sharing. As so far I have only used Norma MRP for my .378Wea Mauser. Very stable and basicly deliveres what the cookbook says it does. 110 grain MRP to a 300grain Swift A-Frame = 908m/sec. I feel I could easely max the performance another 30 m/sec, but it would be for no avail. I want to try 260grain Nosler AB later. They should be able to reach the +3200 ft/sec. Here is a good artical: http://sportsillustrated.cnn.c...G1131618/1/index.htm DRSS: HQ Scandinavia. Chapters in Sweden & Norway | |||
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| one of us |
Yes, that H4831SC load is a good one, and yes, with the 270-grain conventional soft bullet it is a light load. I used IMR-7828 with 300-grain Sierra GameKing and Nosler Partitions, and both were uniform and accurate, about 1 MOA for 3 shots at 100 yards, and both just over 2900 fps with 111.0 grains of IMR-7828. My rifle had a 25" barrel also, still does, a re-chambered CZ 550 Magnum that started as a .375 H&H. Too dear to part with that oldie-goldie. Recoil is mild. Don't worry about it if the rifle is over 9.5 pounds, like my CZ. | |||
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Jens, that article was great fun: "Well, the days of the 100-and 200-pound tusks are gone. Today a 100-pound tusk is considered excellent." LOL! Those were the days. analog_peninsula ----------------------- It takes character to withstand the rigors of indolence. | |||
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| One of Us |
RIP, are you happy with the GameKing performance on game? analog_peninsula ----------------------- It takes character to withstand the rigors of indolence. | |||
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| one of us |
Depends on the application. A 250-grain Sierra Game King from a .375 H&H is excellent for deer and black bear. The 300-grain Sierra GK is great for the .375 Weatherby and .378 Weatherby. They are pretty soft, but they are very accurate and have a pretty good BC. I can interchange the same loadings of Nosler Partition and Sierra Game King 300-grainers, get close to same velocities and POI with same powder charge. They are mainly a reasonably priced plinking bullet, much like the Hornady. A serious bullet is a monometal bullet. | |||
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| One of Us |
"Let every created thing give praise to the LORD, for he issued his command, and they came into being" - King David, Psalm 148 (NLT) | |||
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| one of us |
Powder lots do vary in properties by date of production over the years. Here is the 8th Edition of 2010, Hornady used the F-215 primer and a 26" barrel of 1:12" twist:   | |||
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| One of Us |
I stand corrected. I see that H4895 and H450 are no longer listed; but H450 has been discontinued so that makes sense. The change in the IMR 4350 recommendation is interesting; I find that unusual in a cartridge/powder combination that's so well established. Per the Hodgdon site, the H4831 load is still quite moderate, although the specific bullet isn't listed. analog_peninsula ----------------------- It takes character to withstand the rigors of indolence. | |||
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| one of us |
Here is the Hodgdon Magazine-Manual of 2013 data, bullet make specified. I think this will be very close to reality:  BTW, H4831 = H4831SC here. | |||
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| One of Us |
Well, I ran another series with the 300 grain Hornady round nose, mostly because they're cheap and available. I took my baseline data from the RealGuns .378 article: http://www.realguns.com/articles/406.htm For appropriate powders, it appears that roughly 3 grains of powder is equivalent to 100 fps, one way or the other. Therefore, I backed down the published max loads by 6 grains for H1000, IMR7828, MagPro and RL25 in order to achieve velocities of roughly 2800 fps. Much to my surprise, all of the powders except RL25 behaved exactly as predicted with velocities in the 2825 fps range. RL25 produced velocities a full 100 fps lower than the other powders, which I found interesting. I also ran a series with XMR3100 (discontinued) and the 300 grain Hornady round nose that was six grain higher than my previous load, and that corresponded very closely with the A3100 data published by RIP above, at 2900 fps. Note that the added six grains of powder produced roughly 300 fps increase in velocity, significantly higher than predicted. The 3 grain / 100 fps rule is clearly much safer on the way down than on the way up. The goal of this testing was really just to gain information about my rifle. The good news is that my rifle appears to generate very typical velocities, which I find greatly encouraging, as it appears that most **current** data (thank you, 458 only ) is quite accurate. analog_peninsula ----------------------- It takes character to withstand the rigors of indolence. | |||
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The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Rifles Big Bores Interesting .378 velocity results
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