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Posted: 6/18/2017 8:35:01 AM EDT
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I have a Rossi 92 with 16 inch barrel with 30 inch twist. I've been shooting 240gr subsonic with no issues and would like to switch to 300gr.
I made a few rounds with 300gr xtp and 17gr of imr4227 in magnum brass. I shot a couple with no keyholes at 25yd. Tried with silencer and had no trouble except that the ammo was supersonic(based on sound, no chronograph). Question is what imr4227 load will be subsonic? I've loaded a few with 15 and 16 grains but haven't tried them yet. Interestingly, I've loaded 44spl with 15gr imr4227 and 240gr bullets and it was subsonic, why is that? Also should I worry about the bullets being stable around 1000fps? All the stability calculators say 30in twist is ok with 300gr xtp at 1000fps, but Google is full of people complaining about it, but mostly on Marlin rifles that have 38in twist. |
| You planning to suppress your rossi? Magnum powders like 4227 won't be a good choice. Back pressure really shoots out any unburnt powder in my rossi 45LC. Switched to a faster powder and things are cleaner. I went with trail boss but I am sure there are others that will work. |
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Ive been using bullseye and imr4227 just because I had it already. Both silence fine and the 4227 is sometimes quieter, but I don't know what muzzle velocities are. Ie the 4227 could be much lower velocity than the bullseye and sounding quieter.
I picked up a can of trailboss and titegroup to try but haven't gotten around to them yet. |
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I have a lot of experience loading Bullseye but none using 4227. You need to be careful when reducing some pistol powders. I don't know if 4227 is one of them.
You can safely reduce Bullseye to the point that the bullet won't exit the barrel but of course you want to avoid that. When you are teetering on the edge of super sonic it doesn't take much difference in pressure to go either way. It's very likely that the 15gr 4227 load in 44spl with the 240gr is creating a little less pressure because of the lighter bullet and that's why it's sub-sonic. That same charge with the 300gr bullet may be super sonic because the 300gr bullet creates more initial pressure just to get it moving. Motor |
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The bull's-eye works great, I'm just paranoid of a double charge since it's so little powder. I use 6.0 bullseye with the 240 XTP in magnum brass or with 180 in special brass, both are extremely quiet - any idea what velocities those are? I got the trail boss and tight group specifically to have a larger powder volume, so it is much more difficult to make a big powder error. It's just difficult to use up the bullseye because it lasts forever!
Hodgdon has 44spl loads listed for imr4227 so I'm not worried about it. No input on the 300 grain bullet stability? I'm paranoid about about A baffle strike only because of what ive read on the Internet! |
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According to Lyman cast bullet manual 16.5gr IMR-4227 with 300gr bullet is 837f/s even 19gr is only 1008f/s which is well below super sonic in 44 Magnum.
Your rifle barrel must be tacking on some extra velocity which is actually expected. I'm not "up to speed" on twist rate in pistols but I've never heard of anyone having issues stabilizing 300gr bullets and as I just posted typically velocity from the pistol is sub-sonic. Motor |
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The hodgdon data has a 16 inch barrel a few hundred fps faster than a 8 inch with 4227 since it's relatively slow burning. Haven't been able to find any published subsonic loads from rifle barrels with slower powders.
I tried a box of hornady 44spl that was marked as 950fps and it was well supersonic. |
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