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Old September 26, 2011, 08:35 PM   #1
Brackus
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Question about 9mm load using Unique powder

I've recently been reloading 9mm using 3.4 grains of W231 under a bullet cast of #2 alloy from a Lee 358-125 RF mould, sized to .358. I have found the accuracy of this bullet to be better than the round nose bullet that I was casting, and don't experience the keyholing I would often get with the round nose bullet. To get the rounds using the longer bearing surface bullet to chamber in my CZ 85 and 2075 RAMI, I had to seat it to 1.021 OAL. I was concerned about this at first, but found others who had used the same bullet with a heavier charge of W231 at the same OAL. I adjusted the charge to the minimum that reliably cycled the action, and have found it to be accurate. I have been loading these rounds for a few months and have had good results. Recoil is good, no signs of overpressure, no leading, etc.

The problem I was having with the W231: at 3.4 grains, the volume of the charge is at the lowest limit of what my powder measure will throw consistently, so sometimes the charge will drop very light. It never seems to drop heavy, and I have a routine that I follow where I charge 50 cases weighing every 10th charge as I go, then visually inspect each charged case in a tray before moving on to bullet seating. This process catches the roughly 10% of light charges that are dropped.

Being paranoid, I started thinking about ways to solve the problem, and figured I would have better consistency with a bulkier powder, where I could increase the volume of the metering chamber on the powder measure away from the bottom end of its consistency.

I settled on Unique as a replacement, for its bulk, and its versatility. It will work for all but one of the calibers I reload.

Finally, I get to the question...almost.

I intended to start with 4.8 grains of Unique with the bullet seated to 1.021 OAL, the maximum that will chamber in my CZ's with the 125 grain RF bullet. With 4.8 grains of Unique, the powder will be compressed. I hadn't anticipated how much more volume the powder would occupy than the 231.

The question: Will being compressed in a relatively small case like the 9mm change the burn/pressure properties of the powder in an unpredictable (or dangerous) way? I was cautious but comfortable with the OAL/charge of the W231, but I am less comfortable with the reduced OAL and compressed charge of Unique. Is this a relatively safe path to pursue, or should I look for a powder that is not quite so bulky?

Thanks for hanging in there though my long-winded explanation, and thanks for any insight, guidance or recommendations.

Brackus
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Old September 26, 2011, 09:08 PM   #2
Charlie_98
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On of the worst reloading problems I had was with the 9mm and Unique... which is why I gave up on reloading for it. The very small case volume and the differences between brass (mixed commercial and military) with heavy (but within tolerance) loads of Unique gave me fits... one round would barely cycle the slide on my HiPower, another would show serious primer flow. All in the same magazine-full.

I would recommend segregating your brass (if you need to, by brand) and working up some loads, especially if they are going to be compressed. Maybe start at 4.2-4.4grns Unique and work up from there.
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Old September 26, 2011, 09:22 PM   #3
Loader9
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You're most likely not going to have any problems. I'm using 5.0 grs Unique under a 125 plated and it's an extremely accurate round. No issues with loading or ejecting, just runs like it should in about 15 different pistols including a CZ.
I've used that particular bullet before and never had the issues you apparently are having concerning OAL. When you say 1.021 is the max that will chamber, are you seeing rifling marks or what as it doesn't make sense. I've loaded these out to 1.120 in a CZ and it ran flawlessly.
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Old September 26, 2011, 10:05 PM   #4
Scimmia
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How compressed would it be? I load 4.7gr of Unique under a 125gr LRN at 1.120 without any problem at all. I believe there's a bit of compression, but not much. If you're looking for a light target load, that may be a bit hot anyway, especially at that OAL. I find mine to be similar to cheap factory loads for power, I go all the way down to 3.5gr under a 125gr LSWC at 1.080 for my target load.
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Old September 26, 2011, 10:09 PM   #5
TMD
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Unique is a flake type powder. In some if not most powder measures it doesn't meter very will with charges of less than 5 or 6 gns. Some people have found that if you tap your powder measure before each charge you will get a more consistant load with it.
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Old September 26, 2011, 10:23 PM   #6
Brackus
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Loader9,

Yes, when I work with a new bullet, I always seat one on an uncharged, unprimed case at the maximum OAL specified for the specific cartridge, then slowly seat the bullet deeper until it will just allow the case mouth to make contact as it should. For both of my CZ's this is 1.023 with this bullet. The round nose 125 grain I was using had to be seated to 1.125. I reduce it by 2 thousandths to allow for minute variations in seating depth and bullet diameter, otherwise I find a few rounds here and there that require that I push the slide forward to get the gun into battery. Whatever the bullet is encountering at a longer OAL does not leave spaced marks, but a hardly detectable, smooth shiny band evenly around the bullet just forward of the case mouth, so I don't think it’s the riffling. I had to color the bullet with a marker and rotate the dummy round to clearly see where it was making contact. I think it is just the entrance of the leade. I have read where CZ's have a short leade, and have found where other owners of the CZ 75/85 using this bullet have had to use the same over all length.

Charlie,

I do sort the brass by brand most of the time anyway when using range brass, to try to eliminate variables. For working up this load, I will be using new cases of a single brand.

Thanks to both of you for your input,

Brackus
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Old September 27, 2011, 07:41 AM   #7
Don P
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Some food for thought. Unique does not meter well and will give very poor consistency. I quit using it and have switched to Titegroup. Lee's web sight states that Unique does not meter well and I concur.
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Old September 27, 2011, 08:05 AM   #8
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My only comment is Unique does not meter well. I weigh all of mine. Visual inspection, they differ a little from case to case depending on how the flakes settled. That is my only complaint otherwise I love the way Unique performs. I've settled on 4.9gr of Unique behind 115gr plated bullets myself. Ran from 4.5gr to 5.1gr and everything shot fine out of all of my guns (2 92's, a Cougar, and a 5906). btw - nice post, I'm going to be trying some 124gr plated bullets next.
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Old September 27, 2011, 08:36 AM   #9
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its not a problem. i load 9mm 125g with 4.5-5.8 of unique and its compressed. the oal is 1.100-1.125 in my test loads.

5.8 has just a little more umph.
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