308 Win Question

[74man]

Does the 308 Winchester have to be crimped? I am loading it for my Remington 788 bolt action and some people say crimp and some don't. I know in Autoloaders you should crimp but not sure about bolt action, magazine fed. I loaded them with 150 grain Speer Boattail, so should I crimp them or not or is this going to be a 50-50 answer? Thank you. 74man

 

[CopperClad]

Light crimp. Don't want other bullets in the magazine to set back into their cases.

 

[Roverguy]

Sadly, it depends.

With sufficient neck tension there is unlikely to be need to to crimp for a bolt action from a recoil perspective. There can be certain powders that perform better with a crimp, at least with certain bullet weights. Of course, not crimping can have accuracy benefits.

So, unfortunately, it’s one of those variables that probably needs experimenting. Having said that, 308 with midweight bullets and mainstream powders is pretty forgiving so, if you have a formula you are happy with and it’s delivering consistent accuracy with no crimp, you are winning.

 

[.308 Norma]

Does the 308 Winchester have to be crimped?

No, not necessarily. If you have sufficient neck tension to hold the rest of the bullets left in the magazine of your Remington 788 when you fire it, there's no reason to have the bullets crimped in place. When your 788 recoils, the remaining bullets in the magazine are likely to be slammed into the front of the magazine. If you have insufficient neck tension, they might be shoved deeper into the cases.
I personally have never seen that, and I've loaded for, and fired some pretty darned hard kicking bolt action rifles over the years. The worst thing I've ever seen happen is bullets with soft, pointy lead tips get those tips smashed flat. However, I don't think that hurts much either.

I know in Autoloaders you should crimp

Not even for all autoloaders. I never crimp them for my old Model 100 Winchester .308 - magazine fed.

 

[CarJunkieLS1]

Take a bullet that you have loaded....get your bathroom scale. Take tip of bullet and push down onto bathroom scale til you see 10 pounds...if bullet doesn't move then no need to crimp

 

[PapaG]

No. Not for a 788. Neck tension should be sufficient. Wish I still had any of my old 788s

 

[JO JO]

I do not crimp for my bolt guns

 

[cfullgraf]

I do not crimp bullets in ammo used in my Springfield M1A, 308 Win Garand or Remngton 788 bolt rifle.

I make sure I have sufficient neck tension.

In general, I have several different cartridges used in semi-auto firearms (17 Rem, 204 Ruger, 223 Rem, 22x6.8, 22 Nosler, 6x45, 6.5 Grendl, 6.8 SPC, 30-06, 308 Win, 300 Blackout) and I do not crimp any of them.

Tubular magazine rifles are a different matter but I only have pistol cartridge lever action rifles and those rounds get crimped anyway.

 

[.308 Norma]

Tubular magazine rifles are a different matter

Oh, yeah. I always crimp my 30-30 and my wife's 32 Special bullets in place - both rifles are Model 94s (tubular magazines).

 

[bangswitch]

I don't crimp my rounds for my M1A or my 6.5 Grendel AR, never had any issues with setback on either gun.

 

[Blue68f100]

I don't crimp for bolt rifles if I have enough neck tension to hold the bullet in place. I will crimp only if the bullet cannelure is in the correct position for crimping. If the bullet does not have a cannelure I do not crimp. If your running 0.002"-0.003" neck tension it normally has enough neck tension to hold the bullet. Less than 0.002" it will be a hit or miss depending on how much surface contact you have between the bullet and brass neck.

 

[DMW1116]

I don't crimp my 175 grain SMK loads for my AR10 but do the others. I made a dummy round and ran it through the action from a magazine, releasing the bolt from locked each time. After 3 times through it had grown 0.003". No set back and an average of 0.001" growth, which could have been my calipers and my measuring technique. All the others I crimp at the minimum light crimp from the Lee Factory Crimp Die instructions.

 

[lightman]

I've loaded for a dozen or more 308's and have never crimped.

 

[Charlie98]

I make sure I have sufficient neck tension.

That's the key. Hard brass or worn out brass may (or may not) provide enough neck tension to properly hold the bullet... but even given that, there shouldn't be a problem in most bolt-action rifles.

The question, aside from bullet setback, of 'to crimp or not to crimp' can be a little nebulous... but a general rule of thumb is to not crimp unless you just have to. Even a light crimp can introduce variables between rounds that will affect accuracy and velocity numbers.

 

[Bcwitt]

Not nessesary, but a firm crimp is known to provide more uniform pressure curve. That cannot help but to improve the situation. Custom chambers used in competition guns might be a different story.

 

[Kaldor]

All depends on neck tension. If you have a uniform 2 thou neck tension its not need. Several posters here alluded to brass as it gets used, becomes work hardened. With that work hardening, you will see spring back when sizing the neck. So you may plan for 2 thou neck tension (308 bullet - 306 expander = 2 thou) but in reality that bullet might only being seeing 1 thou or even less if the case is springing back post sizing. Annealing is really the only way to permanently fix this issue as it makes the brass softer, thus it will spring back less, making for more uniform neck tension. More uniform neck tension does increase accuracy and will extended case life as you will see less neck splits.

I do not generally crimp 308 for any gun. That being said I do use a Lee FCD for some press setups. When I load flat base bullets, I use a Lyman M-die to make getting the bullet started easier, but I have to remove that slight flare. I use the FCD to do that, but in no way am I actually crimping. Im just giving the neck a little kiss to remove the flare.

 

[Charlie98]

Not nessesary, but a firm crimp is known to provide more uniform pressure curve. That cannot help but to improve the situation.

The devil is in the details, however. Unless your cases are trimmed to the exact same length, variations in your crimp between rounds can affect pressure and velocity. It's sort of a circular argument... if you are going through the trouble to anneal and turn necks, for consistent neck tension, you likely aren't shooting them in a firearm used for hunting or plinking. Conversely, if you are prepping your brass to that extent, you are likely shooting them in a firearm where an inconsistent crimp might show up in skewed numbers or at the target.

 

[edwardware]

Does the 308 Winchester have to be crimped?. . . I know in Autoloaders you should crimp

No, and No.

You cannot, ever, fix insufficient neck tension by crimping, unless you are driving the mouth into the jacket (which reduces neck tension and harms accuracy unless the bullet has a cannelure for it).

Set healthy neck tension of *3-4 thou in unannealed brass, and skip the crimp unless you're loading for a tubular magazine.

*0.002" is enough, but variation can turn that into 0.0005" if you aren't watching carefully.