9mm reload inconsistency

[bucketobolts]

I had a chance to test a few more loads, 9mm 147gr FPBB Magnus hardcast. I adjusted my Chronograph distance to about 8ft. from my rest. It was a bright sunny day again. I also decided to hand measure each load with my beam scale as I loaded them. All 10 of each recipe were again set at 1.150" OAL.

First load was VV N350 at 4.0gr.

Low/High/Average/Spread/Standard Deviation

806.3/897.2/859.5/90.91/22.78

A little snappy, but not bad; didn't notice a lot of smoke

Second load was Universal at 3.2gr.

Low/High/Average/Spread/Standard Deviation

768.2/818.5/798.6/50.29/17.69

Average recoil, but a good bit of smoke

Third load was Universal at 3.4gr.(max load for this powder in my book for 147gr HDY XTP at 1.100" OAL)

Low/High/Average/Spread/Standard Deviation

831.3/906.4/884.5/75.02/23.81

Not much different in recoil, but smoke is a bit thicker

Fourth load was Unique at 3.7gr.

Low/High/Average/Spread/Standard Deviation

825.5/894.4/866.7/68.93/25.80

Very similar recoil, but very smoky

Fifth load was Unique at 3.9gr.(also max load for this powder in my book for 147gr HDY XTP at 1.100" OAL)

Low/High/Average/Spread/Standard Deviation

889.3/940.9/915.4/51.64/16.27

Not much change in recoil, but I thought I was shooting black powder

I kept my brass(same head stamp) separated for inspection. None of the max loads for Unique or Universal show any signs of high pressures. The Unique brass was very sooty inside. I would like to try a little faster powder. The N350 is #57 on my burn rate chart, and Unique/Universal are #35/36. I usually have Clays on hand, but ran out back in the summer. I couldn't find it locally back then, so I worked up a shotshell load with TITEWAD. I was happy with that. Though I believe it is a bit hot for pistol loads at #3 on my list.

Another note I did a quick cleaning of the barrel with a nylon brush between sessions. After a thorough cleaning at home, I found a bit of leading in the rifling. It sort of sucks to remove.

Also found that the bullet manufacturer, Magnus, recommends an OAL of 1.135-1.140 with this bullet.

Can anyone explain my widespread Standard Deviation?

Edited December 21, 2009 by bucketobolts

[Sarge]

I think the "standard" distance to chrono is 10ft. Some go farther if shooting smokey loads because smoke messes with the chrono readings. So you are probably too close for one thing.

I am not familiar with the powders you used but they may have metering issues because of flake size or whatever. This will cause widespread deviations.

Mixed brass will alter things because not all cases have the same dimensions and case capacity. Velocities will fluctuate because of this as well.

You said it was bright and sunny? Put a USPSA target on top of the chrono with the white side down to give slight shade. This will increase the accuracy of the chrono on too sunny of a day. Stock chrono's prefer bright overcast days.

And finally, even though your SD's are pretty high, due to accuracy of powder measures(=or- .1)and the accuracy of most chrono's combined with the fluctuation of bullet weights, etc... anything under 15 is pretty good with single digits being great AND hard to achieve.

[bucketobolts]

But I weighed all 50 rounds by hand with my RCBS 505 scale. That is the main reason I was scratching my head. I also used all Winchester brass once fired from the same box. I read on this board and some guys are talking about <10SD on there reloads. I could probably get that if I only tested 2 or 3 rounds, but that doesn't represent a good portion when I load a mess.

[Sarge]

Then I guess that leaves too much sun and/or too close? I got an SD under 10 once with a small batch loaded with N320. I hover around 12-13 with solo1000 in 9mm.

[Action Pistolero]

Check the weights of the bullets. Seperate them in piles that weigh the same. Check the diameter of the bullets also. I'm assuming they are lead so they should be .356.

Crimp can be crucial. Measure case wall thickness and multiply by 2. Add bullet diameter and then subtract .002 to .003. Set the crimp die to that figure.

I would try 4.3 grains of WST.

[CocoBolo]

The theory is good everything equal and same brass should come out close. Powder metering aside, the powders you have chosen are a little on the slow side for a non compensated std pistol. I am not sure but I suspect these powders would be more consistent at higher charge rates. N350 is fairly consistent in my 38 Super at 8.0gr behind a 125gr. TruBlue is very similar and it is super consistent its the only powder I have tried where the Crono says DUPE, and the rest are withing 2 or 3 fps, however, it does produce excessive pressure beyond 8.3gr which barley makes major. Popular with the 9 mm crowd.

I would suggest maybe N320, WST, or TiteGroup would give you a softer shooting load, and more consistency at these low charge weights. I always try for a 130pf in minor, if your short you shoot with no score.

[G-ManBart]

But I weighed all 50 rounds by hand with my RCBS 505 scale. That is the main reason I was scratching my head. I also used all Winchester brass once fired from the same box. I read on this board and some guys are talking about <10SD on there reloads. I could probably get that if I only tested 2 or 3 rounds, but that doesn't represent a good portion when I load a mess.

All sorts of things can, and are, going on here. First off, an SD of 15-25 really isn't bad at all. Anything in the single digits is outstanding and will be very hard to get with anything but new cases, super consistent bullets (for consistent seating depth) and a powder that meters extremely well. The important thing will be how they actually shoot. Trust me, you can get 1.5" groups at 25yds with a load that has an SD of 20+.

Keep in mind that even with exactly identical weights, two charges of powder don't give off the identical amount of energy...close, but not exact. Once a case has been shot and resized once it's not as consistent in neck tension and volume any longer. These are small factors, but they get stacked one on top of the other until you read it on the chrono display. The bullets will all be slightly different and they won't be seated exactly the same each time. No two cases have exactly the same capacity. So, add all of that up, and you get an SD of something like 16 with your handload....that's not bad at all really. Try some and see how they group before you get too discouraged!

I would also sugest trying something a touch faster and see what happens. I'm doing some development work with Solo 1000 and 147gr bullets and it definitely doesn't meter that well, but the SD was at 14 last chrono session. Those went into 2" or less at 25yds in my M&P Pro....good enough for what we do. R,

[twodownzero]

You need a faster powder. Your loads are inconsistent because the pressures are too low. That is why they are sooty as well.

Also, you should state the cartridge (I figure it's 9mm luger from the subject line) and the bullet type/weight when you post up load data.

Edited December 21, 2009 by twodownzero

[G-ManBart]

You need a faster powder. Your loads are inconsistent because the pressures are too low. That is why they are sooty as well.

Also, you should state the cartridge (I figure it's 9mm luger from the subject line) and the bullet type/weight when you post up load data.

I got similar numbers (SD of 14) with Solo 1000 and 147gr MG CMJs loaded in once fired Starline brass recently....and that's a much faster powder that was burning clean (225rds and the gun was barely dirty). R,

[bucketobolts]

Sorry 'bout that, I'm working with 9mm 147gr FPBB Magnus bullets. These are my first attempt at hard cast. I'm not so sure I like the smokiness. I'm going to head to the shop tomorrow to get a factory crimp die. I've been using the crimp/seater. I'm also going to see about a faster powder. I guess Solo 1000 would be first choice, then maybe Bullseye or TiteGroup. Somehow I think I have more than one issue compounding.

[Sarge]

Sorry 'bout that, I'm working with 9mm 147gr FPBB Magnus bullets. These are my first attempt at hard cast. I'm not so sure I like the smokiness. I'm going to head to the shop tomorrow to get a factory crimp die. I've been using the crimp/seater. I'm also going to see about a faster powder. I guess Solo 1000 would be first choice, then maybe Bullseye or TiteGroup. Somehow I think I have more than one issue compounding.

Avoid TG with lead if possible especially if you don't like smoke. Solo is a good choice if you can find a small bottle.

[twodownzero]

You need a faster powder. Your loads are inconsistent because the pressures are too low. That is why they are sooty as well.

Also, you should state the cartridge (I figure it's 9mm luger from the subject line) and the bullet type/weight when you post up load data.

I got similar numbers (SD of 14) with Solo 1000 and 147gr MG CMJs loaded in once fired Starline brass recently....and that's a much faster powder that was burning clean (225rds and the gun was barely dirty). R,

An SD of 14 sounds great to me! I go for single digits in my long range rifles, but 14 is perfectly fine for this game.

I have tried AA #5, Power Pistol, Solo 1000, Clays, and perhaps a few others in 9mm. Solo 1000 works great for me. AA #5 worked as well, but it was a bit slow and dirty compared to Clays and Solo 1000. Clays is no good with 147s, though...too dangerous. Solo 1000 seems to have a more linear pressure curve and I'm really happy with the results.

[CocoBolo]

I'm going to head to the shop tomorrow to get a factory crimp die.

I'm also going to see about a faster powder. I guess Solo 1000 would be first choice, then maybe

Here is what one bullet mfg says about the FCD. I had an issue and got a taper crimp die and cured it.

RELOADING TIPS

Make sure to have a good bell on the case so not to shave off the coating during the seating process.

Do not seat and crimp the bullets in the same die. Use a separate taper crimp die.

We highly recommend Dillon reloading equipment.

Do not use a roll crimp or Lee Factory Taper Crimp Dies.The roll crimp will cut through the coating. You must use a taper crimp die.

The Lee Factory Taper Crimp Die will undersize the bullets causing accuracy and fouling problems.

Most of the time a heavier crimp will work better.

Top of Page

this is from http://www.precisionbullets.com/faq.htm

And what they say about powders:

Any powders for cast lead bullets will work for Precision Bullets.

Recommended Powders

Vihtavuori – N-320/N-340

Ramshot – Competition/Zip

Winchester – WST

Alliant – American Select/Power Pistol

Hodgdon – Universal Clays/HP38

Not Recommended Powders

Hodgdon – Titegroup

Vihtavuori – N-310

My powder of choice is WST a little temp sensative but shoots a lot softer than BullsEye, but Solo is a good choice, but varies from lot to lot as it is made by 3 different sub contractors.

[bucketobolts]

Thanks for all the help! I struck out on both the die and powder at the fun store this afternoon. But on the good side I've got a friend that is going to swap me a little Bullseye to experiment with. He also has some Power Pistol that I could use.

I'm using a Lee 3 die set with a RockChucker press. What dies do you recommend?

[G-ManBart]

I'm using a Lee 3 die set with a RockChucker press. What dies do you recommend?

I haven't played around with all of the available dies out there, but two brands are always near the top....Redding and Hornady (in that order). For 9mm, I like a Lee resizing die, any flare/expander die, a Redding Competition Seating Die and a Redding or Hornady taper crimp die. R,

[Duane Thomas]

Several things occur to me. For one, I don't find it particularly difficult to get single digit SDs, even with mixed casings - and I am HIDEOUSLY disappointed if it goes over 20. The keys, I find, are (1) choosing a ball powder that meters superbly - I avoid flake powders like the plague - and (2) perhaps most importantly really watching your crimp. Too tight a crimp will destroy both your accuracy and the tightness of your SD.

Also at eight feet you're probably too close to the skyscreens which can give you inconsistent readings. Ten feet is the classic recommended distance.

Also firing only 10-shot strings isn't really going to give you enough info to get a good picture of what your ammo is doing. Every chrono manufacturer whose literatute I've read recommends 20-shot strings to get meaningful data.

[G-ManBart]

Several things occur to me. For one, I don't find it particularly difficult to get single digit SDs, even with mixed casings - and I am HIDEOUSLY disappointed if it goes over 20. The keys, I find, are (1) choosing a ball powder that meters superbly - I avoid flake powders like the plague - and (2) perhaps most importantly really watching your crimp. Too tight a crimp will destroy both your accuracy and the tightness of your SD.

Also at eight feet you're probably too close to the skyscreens which can give you inconsistent readings. Ten feet is the classic recommended distance.

Also firing only 10-shot strings isn't really going to give you enough info to get a good picture of what your ammo is doing. Every chrono manufacturer whose literatute I've read recommends 20-shot strings to get meaningful data.

One qualifier I'd say to this is that when you're talking about cases, there are some that will make a very big difference. I did a test a couple of years ago and happened to load one batch of .40 with once-fired Win and new Starline cases. Nothing else was changed (both were with Zero 180gr JHPs, Fed SP primer, 4.9gr of N320 and 1.20" oal). The new SL cases averaged 950fps. The once-fired Win cases averaged 991fps. Both had an SD of under 15. If I'd mixed cases the SD and ES would have jumped considerably....41fps is pretty significant from just changing cases. Of course, I had to figure out why and found that the SL cases have quite a bit more volume. Fill up a Win case with powder, pour it into an SL case and it's well below the bottom.

9mm will likely be less likely to experience this, but it's still a possibility. R,

[Duane Thomas]

Yeah, the only thing I really load these days is 9mm Parabellum, with the occasional dip back into .45 ACP.