Will soon start my first reloading experience.  In the Lyman manual, they say I should crimp the bullet in any round used in a semi-auto.  So I am trying to figure out how that is done.  I am using the Lyman dies.

I don't crimp .308, 30.06 or .223.  Never have.  I think most folks will tell you the same thing.

I do crimp pistol rounds because you have to bell the case mouth to get the bullets to start/seat.

With rifle brass you just chamfer the case mouth and the bullet seats fine.

Thanks..appreciate that info.

 

The only rifle rounds I crimp are 300 Blackout supersonics. Without it my accuracy isn't good. It really isn't necessary most of the time unless you are loading pistol rounds.

I have a habit of working up .223 loads with both crimping and not crimping to see which is more accurate. Some bullets are more accurate with a crimp while others prefer no crimp.

My 30-06 loads are not crimped, but I'm going to be starting some Hornady 150gr SST some time in the near future that seat well within the cannelure so I'll try them with and without crimping.

I think neck tension is more important than crimping.

Also, do you have other reloading manuals? It's not a good idea to stick with just one.

I don't crimp any of my reloads (223, 300BLK, 40s&w, 9mm). When I first started reloading I would crimp my 223 rounds because I was worried about bullet setback when getting chambered but that didn't last long and I've never run into any issues without a crimp.

The only rifle rounds I crimp are my lever actions with a tubular magazine. 30-30 and 35rem

I crimp all my semi-auto ammo.  I crimp with the Lee factory Crimp die and not the "taper" crimp built into the seating dies.

If you want to crimp to secure the bullet and to improve accuracy, get a lee factory Crimp die, otherwise for get about crimping.

So you have a suggestion which other manuals I should obtain?  

 

For loads, I would suggest Speer and Sierra. Hornady seems to cautious. Hornady's max loads are quite ofter near the starting loads for Speer and Sierra when I cross reference. My Lee manual id a good job of explaining the process but I usually don't reference it for loads.

All these I mention are the most recent editions.

The Hornady manual is a good choice. It would be my #1 suggestion.

Just so there isn't any confusion the fallowing comments pertain to bottle neck rifle ammo only.

Crimping for a semi auto should be stated as "recommended" but not required.

Like some of the others that posted I typically don't crimp for my AR-15 (.223/5.56) or my 742 Remington (.308 Win.) or even my MAS 49-56. Never have an issue.

I also agree that if you decide to use a crimp use the Lee "Factory Crimp Die"

If the bullet you have has a cannelure, you can go ahead and crimp into the cannelure.  The crimping requires you to have a crimp die ($) and to perform the crimping operation (time) but neither is a big deal.

If you crimp, do it as a separate step - do not crimp simultaneously with the bullet seating operation.

If the bullet does not have a cannelure, I would say don't crimp the bullet.

Thanks..just ordered the Sierra manual and Lee factory crimping die from Cabelas.  The die is only 15 bucks.

I normally do not do anything that deforms the bullet in any way when seating/crimping. That means not crimping in a manner that would form a ring in the bullet. If there is a factory crimp groove I will crimp slightly so that the mouth just touches the bullet jacket, not biting into the jacket. Same with non-grooved bullets like 45 ACP 9MM plated bullets and Sierra match rifle.

Remember that crimping amount is affected by brass length, and rifle brass can vary quite a bit. So, unless you trim before each loading, be careful not to crimp too much or you wiill deform the brass, especially thin stuff like 223. Random crimps will also wreck consistency.

Do not rely on crimps for bullet retention. What is more important is to ensure you have proper neck tension on the bullet. This can be done by measuring the diameter of the neck before, then after seating bullets. You want about .003 with rifle, pistol is kind of variable with some cartridges due to case taper, type of sizing die, etc.

Thanks..I have not seen that info in the manuals..yet.  

 

Pay attention to the cartridge overall length specs. in the reloading manual.

Some .30 caliber bullets have a crimp groove (cannelure) in the bullet that will work fine when seating the bullet to that ring for 30.06 cartridges - but not for .308.

If you seat the bullet till the cannelure in a .308 case the bullet will be seated too deeply and may result in feeding issues or pressure issues.

I've got a bunch of .308 reloads that look funny because that canelure is about 1/4" or so above the case mouth.

The decision to crimp depends on several things.

Some cartridges headspace on the case neck and must be crimped. 45 ACP in a 1911 comes to mind although 45 ACP in a revolver would probably not need to be crimped.

Cartridges loaded in a tubular magazine like a Winchester Model 94 must be crimped. 30-30, 32 Win Spec, 44 Mag etc.

It is recommended to crimp cases for heavy, large caliber revolvers like 44 Mag and heavier. Think high muzzle energy, high recoil, heavy bullets.

Beyond that it falls pretty much to your preference. Precision loads would not likely be crimped.

For cases where the expander die flares the neck where you d not want to crimp, adjusting the seater/crimp die to kiss the case mouth lightly will avoid some feeding problems.

What caliber/weapons are you loading for?

I am starting with .308.

 

For 45 ACP for in an autoloader a taper (not roll) crimp would be indicated. Be sure you know which one you have or you will have head spacing problems.

Here is a link to the section on crimping in the Sierra loading manual. Sierra Loading Manual, crimping

For 308 it depends on the intended usage. For precision shooting and most other uses, you would probably not crimp. A crimp might be used on a 308 if ignition was an issue such as using a powder near or at the slow end of the range for a 308. A crimp would give you better ignition of very slow powders.

Another instance in which the 308 might be crimped would be if the rounds were intended to be stored for many years. Some sort of sealant at the case mouth and primer would also be indicated for long term storage.

I would highly suggest loading for .45 ACP before moving on to rifle rounds - less steps, and will build up your skill level and confidence levels before adding in many more steps with rifle.

Loadbooks USA is inexpensive and covers most mfgrs load data for a single caliber.

I reload for two Armalite AR-10s. I like loading rounds to near maximum magazine length.

My general rule of thumb for "neck tension being enough" is if the bullet is seated at least as far into the case as the diameter of the bullet (.308" in this case).

For 168grn bullets and higher, this problem takes care of itself. However, I also load a lot of 147-150grn bullets for plinking and I do apply a mild crimp on these because at mag length, they aren't seated into the neck very much (especially with boattail bullets).

Also be aware that after 4-5 firings without annealing, the neck tension of the brass may start to decrease regardless of bullet used.

As others have mentioned, correct and consistent neck tension is one of the keys to optimal accuracy with adequate bullet retention for use in semi-automatic rifles.  For the 5.56mm/223 Remington cartridge, if crimping the case mouth improved your accuracy, then the correctness and consistency of your neck tension sucked to begin with.  Crimping the case-mouth of a consistently sub-MOA load (that means multiple 10-shot groups with the extreme spreads less than 1 MOA) will only degrade your accuracy.  This is why Sierra was loath to place a cannelure on their 77 grain SMK for use with crimping in MK262 ammunition.

As far as the question of how much neck sizing is needed to create the correct neck tension, ask yourself this:  At what point are you simply seating the bullet in the case and at what point are you starting to use your bullet as a case neck expander to expand the case neck beyond its original modulus of elasticity while seating the bullet?  I conducted testing using a K&M compression gauge to measure the amount of bullet-pull in PSI and found that no less than 0.0005” of case neck tension, to no more than 0.0015” of case neck tension was the ideal range for optimal accuracy with adequate bullet retention for the 5.56mm/223 Remington cartridge when loading the Nosler 77 grain BTHP.







To demonstrate how crimping the case-mouth of a consistent sub-MOA load degraded accuracy, I conducted a test comparing the average extreme spread of three 10-shot groups fired from 100 yards without any crimp on the case-mouth, to that of three 10-shot groups fired from the same distance with an otherwise identical load, except for the addition of a case mouth crimp.  The results are illustrated in the graphic below in yellow and green; accuracy was degraded by 0.203 MOA.






....

I did some similar testing- I sized some 308 brass without the expander- I measured the necks, then seated bullets. The necks were enlarged about .005 with the bullets seated. I then pulled the bullets and measured the necks again. They were about .002 larger than before I seated the bullets. This leads me to believe that anything more than .003 stretches the brass beyond it's elastic limit and would not increase neck tension. It could cause undue stress on the brass when seating.

Molon; good to see you again.  Appreciate the great info and your research.  As you know I am just beginning this venture.  

Good call, spot on.

Sierra load data is suspect at best, they do not pressure test their loads with Pressure testing equipment,  they test their loads in regular firearms then determine Max loads the same as us, in other words "they guess".  Forget the Sierra manual.

The Lee manual is another one to avoid.  It is nothing but Powder manufacturer's and Distributors (FREE) load data jumbled all together.  It is usually out dated as well.  No sense paying for what is available for free.

Nonsense, complete and utter BS.

There have been more than a few studies/tests with the LFCD vs NO LFCD and in every test, accuracy was improved.

Was your crimp test with a taper crimp applied with a seating die or a Lee factory crimp die.  If it was a LFCD then your test indicates that you do not know how to correctly set up the die.

Here is one such test.

http://www.accuratereloading.com/crimping.html

This is from Ed Harris.

From: [email protected] (Ed Harris)
Subject: Re: To crimp or not to crimp
Date: 21 Nov 90 23:42:20 GMT
Sender: [email protected] (newsout1.26)

I have fooled around with this, and while the factory crimp die makes
alot of sense for ammunition to be used in hunting rifles or
semi-automatics, I don't think you will find any benchresters switching
to it, since application of a heavy crimp usually causes some
deformation of the bullet, which could, though may not make the core
loose in the jacket.  I experimented very briefly with the Lee Factory
Crimp die in a Hunter Class benchrest rifle in ,308 Win. with handmade
bullets and a proven load of 41 grs. of H322 with a 150 gr. bullet and
Federal 210M primers.  Using my usual loading technique of fire-formed,
match prepped cases in a tight-neck chamber this load will shoot from
1/4" to 3/8" 5-shot groups at 100 yards from a 14" twist Hart barrel.
With the factory crimp applied lightly there was no difference.  Taking
the same nominal components but with LC Match brass in a government
chambered barrel with standard .346" neck (vs. .334" in my bench gun,
which cannot use factory ammo) the load averaged slightly tighter when
crimped than when not, but the difference in a "T" test was below
"T-critical" at .95 level of confidence.  Applying a heavy crimp
enlarged groups slightly, but again the "T" test showed no significance
based on a limited sample size of five 5-shot groups for each
condition.  I think the factory crimp die is a good idea for hunting
loads and for semi-automatics, especially for use with slower powders
or those which are hard to ignite.  If you are looking for sub half-moa
groups, you need to be looking at other factors before you try this
type of variable.

I Highly Doubt Mr. Ed Harris is building loads where his Neck tension sucked to begin with!

Here is a small article on crimping.  Note the part about the LFCD and accuracy.

http://carteach0.blogspot.com/2012/05/to-crimp-or-not-to-crimp-using-lee.html

I see that this forum is still infested with trolls.  I'll leave you now to wallow in your ignorance.

.......

I have reloaded thousands and thousands of .223 for general range AR use (not precision shooting).

Several years ago when I first started loading I tried to test both crimp and no crimp.  I was not able to tell a difference.  I couldn't see a difference in the groups or when I tried to measure if there was any setback after chambering.

I went with no crimping and I can't see any negative impact.  My reloads shoot better than any factory ammo and the rounds can shoot better than my marksmanship ability.

I think good neck tension is all you need to keep the bullet from being set back when the round is hard slammed into the chamber.

Other people will tell you that crimping is absolutely necessary on an AR.

By the way, I do crimp my 150 gr .308s that I shoot in my semi autos.

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