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April 21, 2007, 10:03 AM | #1 |
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Join Date: April 21, 2007
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HELP- 45acp loads are waaaay to slow
Here is the problem I'm having. I've been loading Berry's 200 grain round nose flat point's on top of 5.0 grains of VV N320. OAL is 1.200(book calls for 1.24 but these feed better in my gun), crimp is .470-471 According to the powder manual and my trusty LEE book this load should run about 860fps. I checked my loads yesterday and made an average of 723 fps(15 shots). Chrono was set about 11 feet from the muzzle. Thinking maybe my chrono was messed up I checked it against some factory Hornady 9mm. Chrono is fine.
I am dumb founded as what to do next. Max charge is listed at 5.4, but at the rate I'm going I'll never make power factor. I need to make 860 fps for major power factor in USPSA. The gun I am shooting these out of is a Dawson Precision STI Edge with a Barsto bull barrell. Gun has about 1200 rounds through it. I check my powder drops every 25 rounds so I know my charge weight is 5.0 grains. I even checked my digital scale against my balance scale to make sure it didn't go haywire. The powder is only about 3 weeks old purchased from Powder Valley. If someone has any idea as to what is going on I would love to get some feedback on this. |
April 21, 2007, 11:36 AM | #2 |
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I think you are going to be hard pressed to ever get 860 fps with a 200 gr lead bullet and a fairly moderate load of a medium powder. If you must use that bullet, use a larger load of N320 (5.4 gr seems low for a max load with that powder and a lead bullet), or better yet, go with a faster powder like N310 (if you like the VV powders) or maybe Alliant Bullseye (5.0 gr), or ww231 (5.6 gr).
However, a better solution is to use a heavier jacketed bullet with the appropriate powder and load. Always check for signs of excess pressure (and leading) as you increase the load. |
April 21, 2007, 01:09 PM | #3 |
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Join Date: April 21, 2007
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I got my load data from 2 sources: LEE and Vihtavuori. How the heck did their test barrell achieve 855 fps. Load is listed at 5.0 gr, 1.24 OAL VV320 powder. More than likely it was out of a 4 inch barrell(mine is 5). The load data was for a Hornady FMJ. Their data for a LSWC was 888 fps with 5.0 grains. Something is seriously wrong somewhere. Maybe the bright copper plating is playing hell with my chrono. It doesn't read any errors but my velocity numbers are seriously wrong. I shoot 3-4 inches over the the pickup.
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April 21, 2007, 02:11 PM | #4 |
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Join Date: February 2, 2007
Location: Dade City, FL
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I seriously doubt it's your chronograph. Lee is noted for their conservative data. Maybe it's to allow for errors in their dippers and disk powder dispensers, but every Lee load I've tried is below stated velocity.
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April 21, 2007, 02:40 PM | #5 |
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Join Date: March 11, 2006
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Individual guns can vary widely
Although most are close to each other, sometimes an individual gun will be a lot slower or faster than the average. I have seen a 100fps spread between 3 different .357s, all with the same barrel length, all using the same ammo.
You said you checked your chronograph with some 9mm ammo. Fine. But put some factory .45ACP over the chrono from your pistol, and compare the MV to the published stats. If your velocity is significantly below published stats, then you likely have a "slow gun". Tight tolerance "match" type barrels generally produce more friction on the bullet and usually yield lower velocities. It is the "tight" grip on the bullet that gives better accuracy that standard barrels, but you (usually) pay for it with slightly lower speeds. As posted, increase bullet weight, and go to a faster powder for more "power factor". If it was a bigger round, I would say go to a slower powder, but the .45acp just doesn't have the room to get the best out of slow powders like big magnums do.
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All else being equal (and it almost never is) bigger bullets tend to work better. |
April 21, 2007, 04:01 PM | #6 |
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Join Date: April 21, 2007
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Great points...The barrell is a match type Barsto Bull. I guess I'll have to try my loads through a standard 45 barrell and see what the results would be. I'm going to try some near max loads so I can see what if any pressure signs I get, then go from there. As far as a faster powder goes I feel VV320 is a good compromise. Load data for vv310 slows slower specs than the VV320 in a 45.
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April 21, 2007, 04:08 PM | #7 |
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One other thought Chris - check the diameter of the Berry bullets. Let's be sure they are .451-.452 and not .454 or another size. (It's possible.)
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April 21, 2007, 04:13 PM | #8 |
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Join Date: April 21, 2007
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I checked that already. They are in spec
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April 21, 2007, 06:43 PM | #9 |
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Join Date: March 20, 1999
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Good - actually I was thinking backwards anyway. If they had been larger than .451, for example, the velocity should have gone up, not down.
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