Crimping Question

[deeangeo]

Recently I loaded some ammo with a crimp and chose to do two lots, one with a light crimp and the other with a heavy crimp.
Needless to say, exactly the same load spec & recipe for each batch. Plainly the result was two different impact points on the target, but both groups were similar in size i.e. Avg. 1" @ 100yds

The bullet is the Nosler 110gn Accubond - so no cannelure.... any ideas which would be the wisest choice to stay with for the future? Light or heavy crimp?

​I didn't chrono to see if there was a difference in MV. ATB

 

[see it shoot it]

don't crimp that's the answer as there no need,just use a good quality sizing die and keep an eye on how they feel to seat the bullet after a few firing,

 

[Muir]

Crimp if it works and the ony way to see truly if it works is to run your loads over a chronograph. Look at the difference in extreme spread and standard deviation. You will most likely find that the EXS and SD are considerably smaller with the crimped ammo. I have seen this many times and even posted some chrono strips here demonstrating it. Ten or twenty rounds of each will show you. With that in mind, you can crimp to effect. If the numbers tighten up with a light crimp, you're good.~Muir

PS: What kind of crimper are you using? Lee FCD I hope.

 

[deeangeo]

Yup Muir. Lee FCD. Will chrono when I get the time/weather, but just wondered which if any is better...light or heavy crimp.
There's certainly a big difference in impact point.....zero at 100 with heavy is good & a light crimp shows the group POI approx 2" high & 1" left. So all else equal, there's definitely a change. ATB

 

[mereside]

crimping should give more consistant groups than not crimping and you will have to do abit more testing to find what works well, atb wayne

 

[bewsher500]

In my experience it works well on poor quality or poorly annealed brass or those cases that have very thin necks (much more variance in neck tension)
if you are running freshly annealed and neck turned brass then the variance may not be enough to generate an improvement in neck tension consistency.

I had good results from crimping .222 (norma brass, inside reamed, thin necks), clear distinction
crimped .270 (norma brass, thick necks and pretty consistent) and it was barely noticeable if at all
crimped .243 (norma and Lapua brass, Norma inside reamed/outside sized, Lapua needed to be sent away to be annealed as it was very hard) had pretty good results with a noticeable improvement but not enough to justify the extra time to be honest. I had much better results from crimping Lapua than crimping Norma, confirming my suspicion that it works best on brass with issues

I picked up some bullets as part of a job lot of loading gear from a guy who loaded 22-250 and crimped everything
the ones he had pulled had such a heavy crimp mark in them it was probably a good mm all the way round!! in a 5.56mm round!!

I on the other hand back off the crimp die so that the press cams over almost immediately and leaves a very light crimp

 

[Muir]

Yup Muir. Lee FCD. Will chrono when I get the time/weather, but just wondered which if any is better...light or heavy crimp.
There's certainly a big difference in impact point.....zero at 100 with heavy is good & a light crimp shows the group POI approx 2" high & 1" left. So all else equal, there's definitely a change. ATB

Get back out and shoot some more. This time over a chronograph.
I was looking at some files and found the last Chron strip I ran in a .222 using 8202XBR powder which it did not like, but the strips were telling: The Standard Deviation was 18.71 fps with the crimped, 36.31 fps with no crimp. This for 20 shots. (accuracy sucked, but the numbers were good.) ~Muir

 

[deeangeo]

Get back out and shoot some more. This time over a chronograph. I was looking at some files and found the last Chron strip I ran in a .222 using 8202XBR powder which it did not like, but the strips were telling: The Standard Deviation was 18.71 fps with the crimped, 36.31 fps with no crimp. This for 20 shots. (accuracy sucked, but the numbers were good.) ~Muir

Thanks Muir. Both groups with both types of crimp were fine at approx 1/2" MOA @ 100yds......just in different places on the target. No problem there with either Light or Heavy crimp. The next test will be chronoing both to see what ES & SD turn out like. That may then show one or other to be better to use. In which case I can settle on it for the future. ATB