CRIMPING Yes or No

[shoot57]

Just been reloading some 243 bullets and noticed my lee factory crimp die in the box. I used to use it all the time but was put off using it by people telling me it was not needed but reading the lee info sheet they claim more constant velocity and greater accuracy, so i thought do i crimp or do i not …. What do you all think?

[vmax55]

i dont and have never had an accuracy issue

[aister]

It improved things for me with both the .223 and the hornet, the hornet especially.

[rem708]

Only use a crimp if the bullet has a cannelure. Use on bullets without actually damages the wall of the bullet. It also shortens the life of the case dramatically. The bullets should be held tight with just neck tension. If not then this is something that needs urgent investigation.

 

Bullets with cannelure are typically of a 'military' standard where the weapon recoils heavily to such an extent it moves the bullet in the case (generally in the magazine). For hunting this is just never the case unless you are not treating your cartridges with respect.

 

If using a bolt action without any cartridge in a magazine it just a waste of your time and money

[Underdog]

The debate over the advantages of crimp are never ending. Important for heavy magnum big game repeaters and tubular magazines but for accuracy gains....only testing will show!

Will crimping iron out inconsistant neck tensions in a batch of cases ? Never did for me !

Oh and you can crimp an uncannulared bullet. It wont ruin anything but may change the bullets performance.

 

U.

[Bewsher500]

Only use a crimp if the bullet has a cannelure. Use on bullets without actually damages the wall of the bullet. It also shortens the life of the case dramatically. The bullets should be held tight with just neck tension. If not then this is something that needs urgent investigation.

 

Bullets with cannelure are typically of a 'military' standard where the weapon recoils heavily to such an extent it moves the bullet in the case (generally in the magazine). For hunting this is just never the case unless you are not treating your cartridges with respect.

 

If using a bolt action without any cartridge in a magazine it just a waste of your time and money

 

 

sorry but some horrible inaccuracies there

 

1) you can crimp ANY bullet. sure if you mash it with a full cam over cycle it with dent it and could leave a ring. I have a box of these I pulled from someone else's crimped rounds. I use them for plinking and they work just fine.

2) plenty of non military bullets come with canulures (interlocks for e.g)

3) if you are shortening the life of your cases by doing it ......STOP....you are doing it wrong!

 

the point of crimping is to get consistent neck tension,

most commonly seen variances in older brass or mixed brass, brass of an unknown number of firings, brass of poor quality, brass of different lot numbers

 

 

if you have no accuracy "issues" then feel free to ignore the step of a final crimp

 

However, if you don't try it how will you know........you could be one step away from shooting 0.1" groups!!!

 

if you are shooting groups that are "OK" but fancy trying it you may be surprised

 

 

I crimp .222, .270 and 300WM and used to crimp .243! (now sold)

 

my group sizes all came down

simple test

load a lot of identical ammo with trimmed cases (most important aspect of crimping)

crimp 10 of them and leave 10 uncrimped

 

The key to crimping IMO is not to fix the press handle stroke to gauge the pressure but "feel" it

different neck wall thicknesses will give different feel and handle stroke

I keep the die loose in the top of the press and turn back and forth slightly to get the same pressure on each case and keep the press handle in the same region as you pull down. (different stages of the handle arc allow different pressures to be exerted)

this can alter the depth of the crimp very slightly but I prefer that than trying t judge pressure at different stages of the handle arc

 

Do not mash the case! Do it by feel and experiment

you should be able to just see the slight crimp at the edge of the neck but the neck wall should still appear straight, not belled over at the lip

 

shoot 4 x 5 shot groups (two of each)

you can use four targets or two

I prefer 4

 

see what wins

 

if it shows any gains at all experiment with light vs slightly heavier crimp

Edited October 30, 2013 by Bewsher500

[wymberley]

 

 

sorry but some horrible inaccuracies there

 

1) you can crimp ANY bullet. sure if you mash it with a full cam over cycle it with dent it and could leave a ring. I have a box of these I pulled from someone else's crimped rounds. I use them for plinking and they work just fine.

2) plenty of non military bullets come with canulures (interlocks for e.g)

3) if you are shortening the life of your cases by doing it ......STOP....you are doing it wrong!

 

the point of crimping is to get consistent neck tension,

most commonly seen variances in older brass or mixed brass, brass of an unknown number of firings, brass of poor quality, brass of different lot numbers

 

 

if you have no accuracy "issues" then feel free to ignore the step of a final crimp

 

However, if you don't try it how will you know........you could be one step away from shooting 0.1" groups!!!

 

if you are shooting groups that are "OK" but fancy trying it you may be surprised

 

 

I crimp .222, .270 and 300WM and used to crimp .243! (now sold)

 

my group sizes all came down

simple test

load a lot of identical ammo with trimmed cases (most important aspect of crimping)

crimp 10 of them and leave 10 uncrimped

 

The key to crimping IMO is not to fix the press handle stroke to gauge the pressure but "feel" it

different neck wall thicknesses will give different feel and handle stroke

I keep the die loose in the top of the press and turn back and forth slightly to get the same pressure on each case and keep the press handle in the same region as you pull down. (different stages of the handle arc allow different pressures to be exerted)

this can alter the depth of the crimp very slightly but I prefer that than trying t judge pressure at different stages of the handle arc

 

Do not mash the case! Do it by feel and experiment

you should be able to just see the slight crimp at the edge of the neck but the neck wall should still appear straight, not belled over at the lip

 

shoot 4 x 5 shot groups (two of each)

you can use four targets or two

I prefer 4

 

see what wins

 

if it shows any gains at all experiment with light vs slightly heavier crimp

 

Could I just add, shoot the groups through a chrono' and if you're talking non range work in particular, make it 11 of each. Just carry one of each in a pocket for a while, drop them a couple of times and then put them in the magazine and chamber them another couple of times and then measure the COL.

[Bewsher500]

good point

if I had a chrono I would

 

the guys who put me onto crimping showed quite marked drop in ES on 22Hornet crimped vs non crimped, I mean in the region of a 60% drop in the variance of MV

[phaedra1106]

I crimp all my reloads.

 

For the .308Win and 300aac target rounds I use Nosler Custom Competition bullets which don't have a cannelure so those are crimped with a Lee factory crimp. The sub-sonic versions use cast boolits and are factory crimped onto a non-cannelure section of the boolit due to their position in the case.

 

The only ammo that gets roll crimped into the cannelure is for my .44 mag, this is because they are fed from a tubular magazine on my Henry Big Boy.

Edited October 30, 2013 by phaedra1106

[shoot57]

Thanks all very interesting, what i have noticed when seating the bullet in the case is that the pressure needed to push the bullet in does vary a bit so i thought if i crimp then this would even things up and with the lee crimp die i can adjust it to do a light crimp

[aister]

 

 

sorry but some horrible inaccuracies there

 

1) you can crimp ANY bullet. sure if you mash it with a full cam over cycle it with dent it and could leave a ring. I have a box of these I pulled from someone else's crimped rounds. I use them for plinking and they work just fine.

2) plenty of non military bullets come with canulures (interlocks for e.g)

3) if you are shortening the life of your cases by doing it ......STOP....you are doing it wrong!

 

the point of crimping is to get consistent neck tension,

most commonly seen variances in older brass or mixed brass, brass of an unknown number of firings, brass of poor quality, brass of different lot numbers

 

 

if you have no accuracy "issues" then feel free to ignore the step of a final crimp

 

However, if you don't try it how will you know........you could be one step away from shooting 0.1" groups!!!

 

if you are shooting groups that are "OK" but fancy trying it you may be surprised

 

 

I crimp .222, .270 and 300WM and used to crimp .243! (now sold)

 

my group sizes all came down

simple test

load a lot of identical ammo with trimmed cases (most important aspect of crimping)

crimp 10 of them and leave 10 uncrimped

 

The key to crimping IMO is not to fix the press handle stroke to gauge the pressure but "feel" it

different neck wall thicknesses will give different feel and handle stroke

I keep the die loose in the top of the press and turn back and forth slightly to get the same pressure on each case and keep the press handle in the same region as you pull down. (different stages of the handle arc allow different pressures to be exerted)

this can alter the depth of the crimp very slightly but I prefer that than trying t judge pressure at different stages of the handle arc

 

Do not mash the case! Do it by feel and experiment

you should be able to just see the slight crimp at the edge of the neck but the neck wall should still appear straight, not belled over at the lip

 

shoot 4 x 5 shot groups (two of each)

you can use four targets or two

I prefer 4

 

see what wins

 

if it shows any gains at all experiment with light vs slightly heavier crimp

[Harnser]

I always crimp . If you are using your ammo for game shooting you can cycle your ammo through the gun a number of times before actually shooting it . A crimp will stop the bullet getting loose after a number of cycles through the gun .

Over the years I have found crimped ammo more accurate than non crimped ammo . yes , try crimping . You can crimp any bullet and I can assure you that you will not find any crimp mark on the bullet once it has been through the rifling of the gun .

 

Harnser.

Edited October 31, 2013 by Harnser

[theshootist]

Very interesting - I will have to experiment with my .308 and .22-250 as I have never crimped. I had always thought it was just military ammo or for very hard recoiling rifles. In the .308 especially rounds can be sitting in the magazine, chambered, unchambered a number of times before they are actually fired.

[shoot57]

Good point Harnser, as i use my rifle mostly for foxing from a vehicle i chamber the bullet several times, as i don't like the rifle loaded in the vehicle with the safety catch on, as i said i used to crimp everything but was put off and i remember some people warning me that i could get high pressures by crimping … Any thoughts on that?

[Redgum]

As Harnser said. I always crimp now, just for peace of mind, ammo goes in the mag and out without being fired, there is plenty of oppurtunity to hit the heads accidently. I have never found it shortens the life of the cases so why not, the pro's out weigh any possible cons and after all, how long does it take.

[bicykillgaz]

I find crimping more accurate, I did it when I first worked up my load in my hornet and got it stupidly accurate then made a batch up all crimped with no issues. next batch forgot to crimp and had accuracy issues I've since crimped them all and accuracy has improved again.

[Underdog]

Good point Harnser, as i use my rifle mostly for foxing from a vehicle i chamber the bullet several times, as i don't like the rifle loaded in the vehicle with the safety catch on, as i said i used to crimp everything but was put off and i remember some people warning me that i could get high pressures by crimping … Any thoughts on that?

Ahhhr you suffered the opinions of the na-sayers. usually without any experience to back their tales of impending disaster!

 

Your more likely to suffer a major road accident on the way to shooting to ruin your shooting that day than any massive pressure issue from crimping a bullet with thin brass

 

U.

[kent]

I don't think you will raise pressures but you will often make certain brass shoot more consistent. I think the Lee crimp die has a reputation for straightening a hornet round up and this not the neck tension increases accuracy. That said I don't crimp because I haven't found the need with the brass I use, think I might try it sometime and prove that which is just theory at present. Std bullet seating dies are real hard to get concentric rounds with in the Hornet even when really well set up (which is rare) I use LE Wilson Chamber type seaters in an Arbour press

[Harnser]

Good point Harnser, as i use my rifle mostly for foxing from a vehicle i chamber the bullet several times, as i don't like the rifle loaded in the vehicle with the safety catch on, as i said i used to crimp everything but was put off and i remember some people warning me that i could get high pressures by crimping … Any thoughts on that?

 

No you wont get high pressures by crimping . What you will get is more consistent ammo . The crimp will hold the bullet back for a Milli second and give you a more consistent burn ,you will also get more consistent neck tension which is proberbly the biggest anomaly in ammo .

 

Harnser.

[Bewsher500]

I should say that IMO there is only one crimp that works

The Lee Factory Crimp Die (works like a collet)

 

the kind that rely on the ram pressure of the press to force the edge of the neck into a cone is not the way I would be doing it

Some Lee and other seating dies have this feature built in

Edited November 1, 2013 by Bewsher500

[Underdog]

I should say that IMO there is only one crimp that works

The Lee Factory Crimp Die (works like a collet)

 

the kind that rely on the ram pressure of the press to force the edge of the neck into a cone is not the way I would be doing it

Some Lee and other seating dies have this feature built in

Yeah but why but no but why?

 

U