To crimp or not to crimp?

[H2OFUZZ]

I am shooting the 180SMK out of a 7mmSTW at 3140fps would you guys recommend crimping or not? Also do you think that is a good speed for this caliber? Thanks in advance

H2o

 

[backwoods83]

With that much grunt already, use a crimp and you will hurt yourself and the rifle.

 

[Kevin Thomas]

Crimps are fine and dandy for some applications, even necessary for one or two. But for the most part, they're a waste of time if you've got adequate neck tension. They hurt accuracy more often than they help it, but that might be something you want to experiment with. It means an extra step in the reloading process, and whichever type you chose (assuming you do), move in small increments and see what effects it has.

 

[H2OFUZZ]

Ok good to know. I have not been crimping so i think ill keep up with the way i have been doing it. Thanks for all the help.

 

[bowhunthard88]

I recently started crimping my .308 Win. with the Lee Factory Crimp Die. Since then I have noticed a tighter ES and SD reading thru my chrony (low teens ES, like 7-8 SD). No real difference in accuracy, but maybe an average velocity increase of about 20 FPS, I'm gonna try doing this to my .22-250 next. We'll see what happens with that.

I don't anneal my cases yet, I don't believe you have to crimp if the cases are annealed and the neck tension is uniform.

 

[338winmag]

I was on board initially regarding using Lee Factory Crimp dies but now I am on the fence trying to decide if it is even worth the ammo and testing time.

The Positive:
I "think" I got closer ES groups. The reason I say "think" is because one just can't tell with 20 rounds. One would truly think with the logic that smaller ES, the tighter the groups. Again I think I got tighter groups but will have to test some more.....

The Negative:
I work extremely hard in my reloading to get everything as consistent and exact as possible and that goes for my seating depth (for every single bullet). regardless if there is or is not a cannelure, using the Lee Factory Crimp die can and does move the seating depth. If moved, it can be +- .003-.007. Sometimes it doesn't affect the bullet seating depth. If this was predictable, then great, i could take that into consideration when performing the initial seating depth, but it is not.

I called Lee and asked about this. I get an affirmative that it can affect bullet seating depth. So one might get smaller ES groups but if one is changing the seating depth, you can increase your POI groups. Like any other tool, I might probably find the very happy medium for each caliber, but then again not so sure so .......

Thanks
3382Winmag

 

[boomtube]

"..would you guys recommend crimping or not? "

Simple question. Simple answer; try it both ways and tell us what happens.

There's likely to be no real difference at all.

 

[bowhunthard88]

In my testing (most of my initial testing is based @ 100 yds., then I extend the ranges), I did not find 0.005" in seating depth to make a large noticeable difference. 0.010 - 0.020" changes in seating depth, made an actual visible difference in group sizes. But, ES is an important factor, although hard to actually validate unless testing through multiple chronys. I'm not 100% sure if I'll keep crimping, because it should not be necessary with regularly annealed brass (consistent neck tension being the goal). Right now, I'm looking into getting some equipment for annealing my brass, because that's one more thing I do want to try.

I'm not a major expert, so feel free to correct me .

 

[Saracen]

I was on board initially regarding using Lee Factory Crimp dies but now I am on the fence trying to decide if it is even worth the ammo and testing time.

The Positive:
I "think" I got closer ES groups. The reason I say "think" is because one just can't tell with 20 rounds. One would truly think with the logic that smaller ES, the tighter the groups. Again I think I got tighter groups but will have to test some more.....

The Negative:
I work extremely hard in my reloading to get everything as consistent and exact as possible and that goes for my seating depth (for every single bullet). regardless if there is or is not a cannelure, using the Lee Factory Crimp die can and does move the seating depth. If moved, it can be +- .003-.007. Sometimes it doesn't affect the bullet seating depth. If this was predictable, then great, i could take that into consideration when performing the initial seating depth, but it is not.

I called Lee and asked about this. I get an affirmative that it can affect bullet seating depth. So one might get smaller ES groups but if one is changing the seating depth, you can increase your POI groups. Like any other tool, I might probably find the very happy medium for each caliber, but then again not so sure so .......

Thanks
3382Winmag

 

[Saracen]

One of the benefits of crimping, is that it makes the seating depth less critical.
Personally I'd try a very carefully fired group of at least five rounds of crimped, and uncrimped for a direct comparison, preferably at a distance ( longer the better), in calm conditions.

 

[Switchback2]

Only thing you need to crimp is AR type guns.

 

[Lonewolf74]

About 2 years ago hear there was a long thread on the Lee factory crimp die. Many guy's reported better ES and SD in using the crimp with accuracy the same or better then without. I have not extensively tested it but have seen some improvement with it.

So I would say it's worth testing to see for yourself.

 

[bigedp51]

The RCBS AR Series dies come with a taper crimp die and this helped my .223/5.56 loads. And before this the only ammo I crimped was for my 30-30.

"BUT" neck tension also has the same effect along with if you anneal your case necks.

Below is a .223 Lyman type "M" expander die that many reloaders use for their AR15 rifles. Please note this gives .003 bullet grip and bumping the case mouth on to the .226 section of the expander aids straight inline seating.

So as stated above by other posters, try crimping and also the amount of bullet grip and see if it helps.

 

[318lll9740]

If you can shoot clover leafs without a crimp, skip it. Like mentioned bf, only ar/autos that work cases harder would I crimp