357: crimped vs uncrimped 158 LSWC for target

[Catpop]

Somebody asked why I do not crimp my 357 LSWC target rounds. So I got to thinking, if i should.
I did a test at the bench and basically found no difference in accuracy using Missouri boolits (sand bags).
As far as neck tension (boolit grip to case), with the Missouri boolits, which is all I shoot, it takes 5 good whack-a-moles to pull one. Plus a primer with no powder will not dislodge it.
Anyone like to input the subject with there experiences
Tx, Catpop

 

[FROGO207]

Well IF you can shoot a full cylinder full with the lead not backing out and locking up said cylinder there is no need to crimp IMHO. If the lead moves and locks thing up and it does on a stout load then I will crimp it in but otherwise Iwill not as I feel it saves on working the brass. I also bell minimally to save working that brass and use light loads. I also use 38 SPL brass often as it is more economical but that is just me. Just do not forget to remove the lead in the chamber before using 357's if you shoot a bunch of 38 SPL first.

 

[Rule3]

It was I, I confess

If shooting mouse fart 357 Mag loads I guess not much of a crimp is needed as long as the bell/flair is removed. I just always crimp, cause the basics tell me to and there is a crimp groove for some reason?

If shooting full house magnums, no crimp will usually result in bullet pull.

When shooting 38 special full wadcutters from a SW M 52 I just round over the top of the case mouth for feeding purpose

 

[ljnowell]

I've been loading 158 grain LSWC for bullseye match shooting for some time now. I found out early on that a roll crimp wasn't just unneeded, in fact, with fast powders and low velocity it was detrimental to accuracy. I always found better groups without it.

With a LSWC I seat half the forward driving band in the case and just smooth out the flare, no more.

 

[Sunray]

"...takes 5 good whack-a-moles to..." Quit hitting it on a mole and use a rock. snicker.
Crimping target loads is not necessary. Crimping is detrimental to accuracy.
"...mouse fart 357 Mag loads..." .38 Special loads?

 

[stubbicatt]

There are too many factors involved in producing accurate loads to blanketly state that a crimp is detrimental to accuracy, or that it improves accuracy. It is the burden of the hand loader to work through this on his own. Charge weight, primer, powder burn rate, bullet design, overall length, recoil, chamber dimensions, all of these are contributors to good accuracy. What works well in one situation might not be the answer to a different question.

Generally speaking, with revolver and tubular magazine rifle loads, a consistent crimp will render better accuracy, at least in my experience.

 

[Slamfire]

I have read a number of gunwriter articles on this, none of them shot enough ammunition to make a statistically valid sample. I don't know one way or another, I just crimp and all my 357 loads shoot fine.

 

[VanGoghComplex]

I can't speak to accuracy, but I recently learned something else about crimps. I shoot the same caliber and bullet (I get the coated MBC ones) and I found with my slow burning Win296 that a light crimp resulted in brass that didn't expand fully to the chamber wall. The result was a dirty experience. My brass stuck when loading and unloading due to bits of particulate that had wedged itself between the brass and cylinder wall, and I later found tiny dents in my brass! Presumably they got there from trying to expand against said particulate.

It was all fixed when I started putting a heavy crimp on my loads. The extra work required to get past that crimp gave my slow powder time to build enough pressure for proper expansion.

 

[ljnowell]

There are too many factors involved in producing accurate loads to blanketly state that a crimp is detrimental to accuracy, or that it improves accuracy. It is the burden of the hand loader to work through this on his own. Charge weight, primer, powder burn rate, bullet design, overall length, recoil, chamber dimensions, all of these are contributors to good accuracy. What works well in one situation might not be the answer to a different question.

Generally speaking, with revolver and tubular magazine rifle loads, a consistent crimp will render better accuracy, at least in my experience.

No blanket statement is ever correct regarding ALL loads. I can say without a doubt though that when loading light loads with fast powders a crimp is detrimental to accuracy. I've put more than enough testing in this with different bullets and powder while loading for bullseye competitions to know this as a fact.

 

[murf]

depends on what powder you are using. bullseye, being quiet fast, builds up pressure very quickly and the inertia of a 158 grain bullet is sufficient, on its own, to build sufficient and consistent pressure. a slower powder will probably need the help of a crimp to build sufficient pressures. chose the powder, then apply the appropriate crimp for that powder (and bullet). all part of working up a load.

murf

 

[Buckeye357]

I put a good crimp on everything I load . The crimp grove is there for a reason and brass is cheap.

 

[GarrettJ]

Interesting this should come up. I was just shooting this morning, comparing crimped vs. uncrimped loads.

I was shooting some 158 gr. XTPs with a near-max load of H110 through a 14" T/C Contender. Being a single-shot, I don't have to worry about bullet jump in the cylinder. I also wanted to stretch these out a little and see how they perform at distance. The gun is currently sighted at 100 yards, and I was shooting at the 200 yard line. I did not adjust the scope, and you can see where this load drops around 15 inches at 200 yards.

I shot two 10-round groups. Both had been loaded the same, then half run into the die just far enough to remove the case mouth bell. The other half were given a firm roll crimp.

The crimped load gave a slightly better group of 5.5". Uncrimped gave a 7.5" group.

I was interested to see how the uncrimped loads would perform, as this powder is often reported as being inconsistent when not crimped. It turns out they were not as far apart as I'd thought. The crimped load had an SD of 16.5 and a spread of 45 fps. The uncrimped load SD was 19.7 with a spread of 63 fps.

If I were to hunt deer with these loads, I'd feel comfortable shooting up to 200 yards (adjusting appropriately for drop), but I see no reason not to crimp, based on this.

 

[Walkalong]

That is full bore jacketed loads vs light lead target loads the OP asked about. I am not sure anyone doesn't crimp full load jacketed .357 ammo. Your results there are typical in my limited experience with full bore jacketed .357.

I agree that uncrimped tends to work better with light lead target loads.

 

[joneb]

I use a crimp on my revolver loads, how much is determined by bullet pull via my calipers.

 

[joneb]

sufficient and consistent pressure. a slower powder will probably need the help of a crimp to build sufficient pressures. chose the powder, then apply the appropriate crimp

I agree.

 

[cfullgraf]

These days, i load heavy 38 Special loads in 357 Magnum cases for my 357 Magnum shooting. I taper crimp these loads mostly to remove the flare in the case mouth. This is more than adequate for my use.

if I ever go back to full house 357 Magnum loads, I will certainly do a roll crimp sufficient for the application.

 

[TimSr]

OP did not mention what load or what gun. I crimp everything. My 357 cast SWC loads are full power 357 loads, and I can guarentee the bullets will not hold in my 6" GP100 without a crimp.

 

[PJSprog]

I'm in the camp of crimping everything for revolvers. I always have. Even my .38 Special loads get a light roll crimp. .357 Magnums go through my Lee FCD.

 

[627PCFan]

FWIW, I just remove the flare from wadcutters, but for the MBC 158 SWCs, I roll crimp them hard to the groove. My testing shows tighter groups, I'm assuming because it allows pressure to build consistently.

 

[Average Joe]

I just remove the flare, and slightly roll it in the groove.

 

[lckdnldd]

I crimp all my revolver loads. That is how I was taught. I will add, I do not load powder puff/light target loads. Most of what I load are medium to warm/hot. Of course within printed load data charge weights.

 

[digid]

I found using Trail Boss in a 38 Special with 158 SWC that too much of a crimp was causing my bullets to not be as accurate. Now these are light loads for paper. If I do a very light crimp, just enough to remove the bell and maybe just a little more I get better accuracy. Never had a problem with these loads shifting in the cartridge. I marked a few rounds with a black sharpie marker shot 5 and checked the 6th and could not see any movement. So that is how I crimp my lighter target loads now. For full up 38's and 357's I put more crimp in. I have done the same check with the marker with these.

 

[joneb]

I hate to say it but this could be a "that looks about right" kinda thing

 

[ljnowell]

I found using Trail Boss in a 38 Special with 158 SWC that too much of a crimp was causing my bullets to not be as accurate. Now these are light loads for paper. If I do a very light crimp, just enough to remove the bell and maybe just a little more I get better accuracy. Never had a problem with these loads shifting in the cartridge. I marked a few rounds with a black sharpie marker shot 5 and checked the 6th and could not see any movement. So that is how I crimp my lighter target loads now. For full up 38's and 357's I put more crimp in. I have done the same check with the marker with these.

That's what most everyone loading light loads would find if they tried it.

 

[Bama Drifter]

My "light target" .357mag load is 158gr LSWC over 6gr of Unique. So +1 for no roll crimp. In the fabulous little set of Lee Dies I only use the decapper/ resize die; the flaring die and the seating/taper die. I see no need to use factory crimp die unless shooting out of a lever action or loading up to extra hot YMMV