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Posted: 10/17/2011 6:26:00 PM EDT
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I have just started reloading and have a question about a load that I am shooting through my M&P Pro 9mm. I have started shooting USPSA in the production division and based on a friends recommendation I loaded up a round with the following.
147gr FP (Precision Bullets) 4.6 grains of Vihtavuori N320 My point of impact with factory 115gr. FMJ's have always been a little low at 15yds. but with this load my POI is about 3" high and 2" right. What is causing this and what can I do to remedy it? I like the way these loads have less recoil than factory loads but I'm not sure what to do about the POI, should I try lowering or increasing the powder? |
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You need to use proper load data for all loads. NO guesses, and no experimentation.
The bullets are likely striking high due to their weight. The 147s are the heaviest bullets for the caliber and they start/move slower, which leaves them in the barrel a tiny bit longer, which means the muzzle has begun rising from recoil. Use a lighter bullet, as the 147s are easy to seat too deeply, which raises pressures GREATLY. Most guys use either 115s or 124s. Be careful. 
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The rear sight is drift adjustable for windage, loosen the set screw and you can drift it a bit, I use a brass punch for drifting, to move the impact left, move the rear sight left, a little bit at a time. http://mp-pistol.com/ |
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Have deleted two responses because they were less than kind. Don't go to others or trust others for charge weights. Use published data, in your case it would be VihtaVouri website.
I load a lot of 147 grain 9mm and 320 would be my next to last choice using VihtaVouri. 3N38 is what you should be using for 147 grain. Posted Via AR15.Com Mobile |
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Vihta Vouri lists N320 for jacketed with charge range being 3.1 grains (784fps) to 3.9 grains (978fps). VV doesn't have a listing using N320 with plated or lead because it's too fast a burning powder for too large a bearing surface.
At 4.6 grains you're probably pushing close to 1100 fps. Just measuring velocity your ok. Using 3N38, VV lists velocity max at 1207 fps. What's not taken into account is pressure. 4.6 grains is way over pressure Look, 147 grain and 4.6 grains N320 is probably a common load in USPSA world. I wouldn't have been a bit surprised if your friend had recommended magnum or rifle primers too. USPSA shooters pull out all the stops to achieve major power factor with as low a recoil as possible. Keeps muzzle straight and follow ups quick, right ? Still, 4.6 grains is over listed maximum and not to be lightly played with. I know guy's who play USPSA and how they load. The ones I know worked their loads up carefully and use fully supported chambers. The reason POA to POI is off as much as described. Your over driving the bullet. You could drop powder charge to 3.9 grains and see where you're at. You really, really need a Vihta Vouri manual and read pages 1 through 98. We always advocate Lyman #49 or Lee 2nd Edition. Vihta Vouri in your case is the book to start with. You will thank me after reading and possibly loose a little faith in your friend afterwards. Reloading isn't as casual as some make it to be. It's serious stuff. |
| I really am thankful for all of the advice you guys are giving. I have about 2k of the 147gr. lead bullets and would like to be able to use those if possible. What is a good powder that you guys recommend for pushing the heavier lead bullets? And yes, my friend is a USPSA shooter and that is his load but i don't want to use it if it could be dangerous. We did get an average of 917fps over a 10 shot string through a chrono. |
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Quoted:
For low recoil, the lighter the bullet the better. To get the POA=POI, the lighter bullet will also shoot lower because of what beekeep said above. Did you work this load up or just pick a number and load them? Posted Via AR15.Com Mobile Actually, not wanting to be contradictory Wizzo. Using lighter bullet to acheive lighter recoil isn't entirely true. Try 3.6 grains of Hodgdons Clays with 230 grain round nose plated or jacketed bullet. Very soft recoil and extreemely accurate. 147 grain 9mm when used with a fast burning powder like N320 will produce a very light recoil. The problem is powder can burn too quicly, not produce enough gas to drive a 147 grain adequately because bullet is long. Another powder that's real popular with 147s is Titegroup which has close to same burn rate as N310. Using either powder leaves cartridge vulnerable to secondary ignition or "stem wave" as Vihta Vouri refers. Both powders produce velocity and low recoil. |
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Quoted:
I really am thankful for all of the advice you guys are giving. I have about 2k of the 147gr. lead bullets and would like to be able to use those if possible. What is a good powder that you guys recommend for pushing the heavier lead bullets? And yes, my friend is a USPSA shooter and that is his load but i don't want to use it if it could be dangerous. We did get an average of 917fps over a 10 shot string through a chrono. Is he moly coating bullets ? |
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Quoted:
Quoted:
I really am thankful for all of the advice you guys are giving. I have about 2k of the 147gr. lead bullets and would like to be able to use those if possible. What is a good powder that you guys recommend for pushing the heavier lead bullets? And yes, my friend is a USPSA shooter and that is his load but i don't want to use it if it could be dangerous. We did get an average of 917fps over a 10 shot string through a chrono. Is he moly coating bullets ? These are the bullets I'm using Precision Bullets |
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This is from FAQ section of Precision's website.....btw, this guy doesn't answer his phone.
Q: What is the coating? A: We use a proprietary solid dry film lubricant. This is similar to the moly/poly coatings on the market but is much tougher. We bake the coating onto the bullets, then restrike the bullets in carbide dies after the coating is applied. When you said velocity was chronographing under 1000 fps when data supports velocity close to 1100 fps, I knew something was up. Numbers weren't adding up at all. Moly is a data game changer because moly actually lowers velocity so it takes more powder to push. Now N320 makes a little more sense to use than before. I still don't believe it to be the right powder combination. Now instead of thinking bullet is traveling too fast my thought is traveling too slow. Trying to diagnose an issue from a keyboard without ALL the facts is a tad bit difficult. Here's the bottom line. You need a foundation to work from, meaning start reading up. My guess and that's what it would be now moly is in picture is to switch powder to 3N37.or N350. Need more gas behind bullet is my guess and it is a guess. Brian Enos forum may be a better place to ask this question. It's geared more USPSA. |
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