Crimp Test

[Darrell]

I decided to do an experiment with crimp today. I always hear some folk on the forum talking about minimal to no crimp, and yet the bullseye shooters are crimping more. I ran a test with my Dan Wesson PM-9 in the ransom rest at 25 yds. I used to crimp my 9mm at .3785 but after today I will be crimping .375 like Neal with the bullseye shooters recommended. The load is my steel load with Montana Gold 95gr JHP behind 4.6gr of Solo 1000. The theory behind more crimp according to Neal, and Sierra bullets is to give the cartrige better ignition and it also work in my Production load with N340 and M.G. 121 IFP. Below is the data.

Edited October 23, 2010 by Darrell

[JThompson]

I decided to do an experiment with crimp today. I always hear some folk on the forum talking about minimal to no crimp, and yet the bullseye shooters are crimping more. I ran a test with my Dan Wesson PM-9 in the ransom rest at 25 yds. I used to crimp my 9mm at .3785 but after today I will be crimping .375 like Neal with the bullseye shooters recommended. The load is my steel load with Montana Gold 95gr JHP behind 4.6gr of Solo 1000. The theory behind more crimp according to Neal, and Sierra bullets is to give the cartrige better ignition and it also work in my Production load with N340 and M.G. 121 IFP. Below is the data.

That's interesting, but was it all the same headstamps, all shot the same amount of times? Both could affect the results....

JT

[gng4life]

Just curious, did you logged the fps for each load with the avg, hi, lo, etc? Thanks...

[Darrell]

Just curious, did you logged the fps for each load with the avg, hi, lo, etc? Thanks...

All winchester once fired brass, Federal primers, avg is group size, not chrono data.

I didn't chrono with this batch, but I have chrono data for the other day. I wanted to get rid of some solo so I used it, but best accuracy is with N340, 5.4 grs. This is my steel load.

Edited October 23, 2010 by Darrell

[Darrell]

I decided to do an experiment with crimp today. I always hear some folk on the forum talking about minimal to no crimp, and yet the bullseye shooters are crimping more. I ran a test with my Dan Wesson PM-9 in the ransom rest at 25 yds. I used to crimp my 9mm at .3785 but after today I will be crimping .375 like Neal with the bullseye shooters recommended. The load is my steel load with Montana Gold 95gr JHP behind 4.6gr of Solo 1000. The theory behind more crimp according to Neal, and Sierra bullets is to give the cartrige better ignition and it also work in my Production load with N340 and M.G. 121 IFP. Below is the data.

That's interesting, but was it all the same headstamps, all shot the same amount of times? Both could affect the results....

JT

Yes, once fired winchester, fed primers. I do all my testing with once fired brass and same headstamp.

[gng4life]

Just curious, did you logged the fps for each load with the avg, hi, lo, etc? Thanks...

All winchester once fired brass, Federal primers, avg is group size, not chrono data.

I didn't chrono with this batch, but I have chrono data for the other day. I wanted to get rid of some solo so I used it, but best accuracy is with N340, 5.4 grs. This is my steel load.

I guess you like the 340 then? I looked up a bunch of loads on here and came up with a few different recipes from other members but finally ended up with a load of 4.9 gr of N320 with the MG 95 gr JHP. I shot some today and it's like a .22 in my shorty Open gun. Have you tried any N320?

Were the crimps and groups similar with the N340 test? I never really check my crimp that much but I am going to do that tonight. I normally just crimp it enough to keep the bullet in the case, that's it. Thanks for the info!

[Darrell]

Just curious, did you logged the fps for each load with the avg, hi, lo, etc? Thanks...

All winchester once fired brass, Federal primers, avg is group size, not chrono data.

I didn't chrono with this batch, but I have chrono data for the other day. I wanted to get rid of some solo so I used it, but best accuracy is with N340, 5.4 grs. This is my steel load.

I guess you like the 340 then? I looked up a bunch of loads on here and came up with a few different recipes from other members but finally ended up with a load of 4.9 gr of N320 with the MG 95 gr JHP. I shot some today and it's like a .22 in my shorty Open gun. Have you tried any N320?

Were the crimps and groups similar with the N340 test? I never really check my crimp that much but I am going to do that tonight. I normally just crimp it enough to keep the bullet in the case, that's it. Thanks for the info!

N340 has been the most accurate powder at 130-135 power factor for me with 124 JHP's which is what I shoot in Production. I tried the 95 jhp just to see how they would work at our steel match, and they do great. I haven't tried them in my open gun yet. I shoot 9major, and .38 super and my gun runs best at 170 PF. Too much dot movement trying to load down, so I just keep it at major so the dot doesn't move as much. I used to use N320 but like N340 better.

[noylj]

1) Too few data points. Sampling way too small.

2) Did you do a t-Test to eliminate the null hypothesis at the 90 confidence level?

[Darrell]

1) Too few data points. Sampling way too small.

2) Did you do a t-Test to eliminate the null hypothesis at the 90 confidence level?

WTF?

No

[G-ManBart]

Were these done on a Ransom Rest, or similar? How many rounds per group? I'm not sure I would take away anything from that, other than that .380 was clearly not as good as the others. The absolute best group, by a fair amount, was with the second to least amount of crimp. If the tighter crimp number better, I'd expect to see somewhat different numbers.

[Darrell]

Were these done on a Ransom Rest, or similar? How many rounds per group? I'm not sure I would take away anything from that, other than that .380 was clearly not as good as the others. The absolute best group, by a fair amount, was with the second to least amount of crimp. If the tighter crimp number better, I'd expect to see somewhat different numbers.

I'm going to do another test with more rounds, thinking of doing a 50 round test of each crimp with my N340 and 121 IFP load. I think 50 rounds of each in the Ransom rest should validate it. I will use same brand of once fired cases. Wish I had inserts for my EAA because thats my most accurate 9mm, but the Dan Wesson will prove my theory.

[DougCarden]

When I started loading 9mm for Bianchi, I did a lot of research and experimented with crimp. I miked, and miked, and did all kind of measurements, and spent days at the range. Here is what I found out for the 9mm, which mirrors Neil from NSK's stuff....

When I set up the taper crimp die, I increase the crimp until I pull the bullet and get a faint line around the bullet. NOT a deformation of the bullet, but just a faint line showing the case mouth is getting pushed into the bullet. This works ONLY with a jacketed bullet, not a plated one.

Then I check to make sure there is a smooth transition from the case mouth to the bullet. In the 9mm if you leave a sharp edge on the crimp you will have phantom FTExtract from the chamber, as the spent case hits the sharp edge of the case in the magazine when it gets pulled out.

Lead bullets need a little more crimp than a jacketed, but not much.

In Summation, hence, ergo.....

I agree with Darrell's observations, and I appreciate him taking the time to post his information.

Thanks again, Darrell!

DougC

[Darrell]

When I started loading 9mm for Bianchi, I did a lot of research and experimented with crimp. I miked, and miked, and did all kind of measurements, and spent days at the range. Here is what I found out for the 9mm, which mirrors Neil from NSK's stuff....

When I set up the taper crimp die, I increase the crimp until I pull the bullet and get a faint line around the bullet. NOT a deformation of the bullet, but just a faint line showing the case mouth is getting pushed into the bullet. This works ONLY with a jacketed bullet, not a plated one.

Then I check to make sure there is a smooth transition from the case mouth to the bullet. In the 9mm if you leave a sharp edge on the crimp you will have phantom FTExtract from the chamber, as the spent case hits the sharp edge of the case in the magazine when it gets pulled out.

Lead bullets need a little more crimp than a jacketed, but not much.

In Summation, hence, ergo.....

I agree with Darrell's observations, and I appreciate him taking the time to post his information.

Thanks again, Darrell!

DougC

Thanks Doug, I spoke with Neil at length and followed his advice also. I'm doing another experiment today with another load just to see, and I'll chrono these to see if there is a difference. I like tinkering anyway just cause thats my nature.

[Hi-Power Jack]

When you say the N340 is more accurate than N320:

1. have you tried 147 grain bullets?

2. how much more accurate? What size 10 - shot groups

are you getting with the N340 and the N320?

I'm almost out of WW231 and thinking of trying the N320,

from what I'm reading, but now wondering if I should try

the N340 as well.

Any disadvantages to the N340?

Thanks,

Jack

[Darrell]

When you say the N340 is more accurate than N320:

1. have you tried 147 grain bullets?

2. how much more accurate? What size 10 - shot groups

are you getting with the N340 and the N320?

I'm almost out of WW231 and thinking of trying the N320,

from what I'm reading, but now wondering if I should try

the N340 as well.

Any disadvantages to the N340?

Thanks,

Jack

I have tried 147 gr bullets, but I prefer 124's. The best 10 shot group at 25 yds from a ransom rest in my PM-9 was 1.5" with N340, 1.51" with Tight Group, and 1.55" with N320. The N340 load is a little snappier than N320, the standard deviation is better with N340 also. Best 147 accuracy was 1.87" with 3.6 of 231

[Darrell]

Tested again today with another bullet. Here are the results Tighter crimp performed better. This is 4 5shot groups fired from Ransom Rest at 25yds.

Gun Bullet Wt Powder Chg Case Primer OAL Hi Low Avg ES SD Best gp Worse gp Avg gp Crimp

PM-9 M.G. IFP 121 N340 5.4 Speer Wolf 1.12 1107 1040 1070 67 18 1.125 2.5 1.85 0.375

PM-9 M.G. IFP 121 N340 5.4 Speer Wolf 1.12 1088 1003 1051 85 24 1.87 3.375 2.55 0.380

Edited October 25, 2010 by Darrell

[DougCarden]

Jack, VV 340 is almost the same burn rate as 330, which is IMHO the optimal .355 bore powder, with WSL just in front of that. 320 will be a little bit softer, but the 340 will give you great accuracy when you find the sweet spot. Not to say that W231 is not a good 9mm powder, as it is and I use it alot with lighter loads (Steel Challenge).

I would get a pound of each and try them up against your 231 loads and see if there is any difference to you. If it ain't broke, don't fix it...

Good luck,

DougC

[Hi-Power Jack]

Jack, VV 340 is almost the same burn rate as 330, which is IMHO the optimal .355 bore powder, with WSL just in front of that. 320 will be a little bit softer, but the 340 will give you great accuracy when you find the sweet spot. Not to say that W231 is not a good 9mm powder, as it is and I use it alot with lighter loads (Steel Challenge).

I would get a pound of each and try them up against your 231 loads and see if there is any difference to you. If it ain't broke, don't fix it...

Good luck,

DougC

Thanks, Doug & Darrell - sounds like I just might stay with my 3.8 gr WW231 -

seems pretty good to me - wondering if the N320,330 or 340 might be better, but

doesn't sound too much better? Maybe I'll try one pound of each, and see what

happens - but the 147's seem more accurate in my Browning Hi=Power. Maybe I'll

try some of the .356's or .357's though since I don't get grooves all around

the spent bullets - only about two-thirds of the way around - with both MG

and Zero 147's at .355".

Jack

[jtaylor996]

1) Too few data points. Sampling way too small.

2) Did you do a t-Test to eliminate the null hypothesis at the 90 confidence level?

Haha... this is a joke right? He's not publishing a paper in a journal about it...

If not, then what's your dog in this race?

[briansea2]

1) Too few data points. Sampling way too small.

2) Did you do a t-Test to eliminate the null hypothesis at the 90 confidence level?

Haha... this is a joke right? He's not publishing a paper in a journal about it...

If not, then what's your dog in this race?

exactly in fact I say "BURN HIM HE'S A WITCH"

TORCH HIM. BMP.bmp

[rhyrlik]

Could you tell me more about the heavier crimp and Bullseye shooting? Is there a link you can direct me to? I have always believed that taper crimp does nothing for autoloaders, but your experiment shows there is a velocity increase. I have also noticed that Winchester factory 9mm is crimped more heavily than the other brands. I have always crimped minimally, believing that an unmolested bullet shoots better.

[Darrell]

Could you tell me more about the heavier crimp and Bullseye shooting? Is there a link you can direct me to? I have always believed that taper crimp does nothing for autoloaders, but your experiment shows there is a velocity increase. I have also noticed that Winchester factory 9mm is crimped more heavily than the other brands. I have always crimped minimally, believing that an unmolested bullet shoots better.

Talk with Neil of NSK he can explain it better

Neil

NSK Co.

410.833.2100 | Fax:410.833.2101

nsk@nsksales.com

www.nsksales.com

[rhyrlik]

I shot him an email. Thanx.

[DWFAN]

I shot him an email. Thanx.

I would be interested in the results of the discussion if you dont mind sharing later one.

[rhyrlik]

He said the crimp is for reliability, not improved combustion, although it does help combustion a bit. I don't believe that a taper crimp increases bullet pull because the mechanical lock is too slight, as opposed to a roll crimp into a pronounced crimp groove. My solution to bullet pull consistency is to clean the insides of my cases. Bare brass on copper creates more friction than carbon coated brass. That's why you'll see a lower ES using new brass than when using 1x fired. Someone here did a comparative test using new vs fired brass and new brass cut the ES in half.