Crimping cast bullets for .308 necessary???

[LORH1]

I'm pretty new to casting and I'm currently casting for my .308 BA.
My question is, is crimping necessary?

[Recycled bullet]

I believe crimping helps with feeding in my guns with my bullets, I suspect it helps with consistent ignition which I believe I can see on target and I don't have a chronograph so I cannot tell you exact velocity or extreme spread or data points like that .

For my 308 ammo I like to expand necks with an N OE M Style case neck expander. It's a little metal tool that fits inside of the Lee Universal expander die. Then I seat and crimp in separate steps. For 308 Winchester I lightly or moderately crimp using the Lee collett crimper. In my opinion it makes my ammunition more consistent and anything that makes my ammunition more consistent pleases me.


Are you trying to decide whether or not you want to crimp? Make some test loads/dummy cartridges (no powder and no primer) of 5 cartridges crimped, and 5 cartridges without it.
Then check for proper feeding by loading up the dummies into the gun and operating the action.


What bullets are you shooting? I'm having tons of fun making plinking bullets with a plain base 150 grain and 225 grain pointy Noe bullet mold. I am powder coating them and sizing them 309.

Have you shot your loads yet? Do you trim your brass?

I find trimming brass helps greatly with expander and crimper consistency. I used the little crow Gun Works trimmer installed in a half inch electric drill and did an entire large wheel bearing box full of Winchester 308 in about an hour and a half, then a day later swapped the adapter and trimmed a whole small metal coffee can of 300 Blackout brass, that I'm shooting the same bullets in also.

I recommend mechanics thin rubber gloves if you're going to trim that many pieces of brass, and do it over a big trash can, because that brass trimmings (swarf?) is dangerous do not scratch your face when your hands are covered in it.

[Kraschenbirn]

In my experience, a heavy crimp isn't required for cast boolits unless you're pushing your loads to a point where movement of the boolit in the case neck (due to recoil) might become a factor. For .308s, my procedure is almost exactly the same as the previous response: expand necks with an NOE tool, seat, and crimp lightly (just enough to remove any flare of the case mouth). Only real difference is that I size my boolits to .311.

Bill

[charlie b]

I only shoot from the bench so I seat my bullets to jam a bit into the rifling. I find it improves accuracy a bit. But, if you need to remove the cartridge from the gun (as at the end of a hunting day) it is not very convenient.

[MostlyLeverGuns]

I crimp just enough to remove the 'flare' from the 'M' type expanders that I use. Some of the rifles I shoot lack a chamfer into the chamber, for those I crimp just enough to get smooth feeding. For my tube feed lever actions, I crimp just enough to keep the bullet from telescoping into the case under spring and recoil pressure. I mostly use the Lee Factory Crimp Die on most RIFLE cartridges, though the crimp step in most makes of seating dies works just fine, if adjusted separately or you take the time to get the seating AND crimping set-up correctly. I load all my ammunition to feed from the magazine(mostly Savage 99's and Marlin's), so most have some sort of crimp. I do use Redding Taper Crimp Dies for many of my .308 and .223 jacketed loading, but the Lee Factory Crimp Die also works just fine and might be more versatile and easier to adjust. I do trim all my brass before loading, at least the first time and anneal on a regular basis, mostly every load cycle, but I do have a mechanical annealing machine.

[popper]

Generally you will need to flare the mouth of the case for cast. Then remove the flare after seating the bullet. I use the FCD for 308. Neck tension generally works fine for 308W, bullet dia. a few thousands greater than neck inside dia. Works for jacketed or cast. For a .308 bore, expand to 308 and use a 310 cast bullet generally works.

[Winger Ed.]

I load a cast 170RN for my M1A. I put a slight crimp on them to take the 'edge' off the case mouth.
I don't exactly roll it all the way into the crimp grove, but if the boolit moves back, it will hit the driving band
and stop at the top of groove.

It's a rack grade Springfield with original open sights.
I don't shoot much past 100 yards any more, and the cast load will hold almost as tight as the 147gr GI bullet pulls
I mostly shoot in it.

[Rapier]

I do not crimp cast past a straight neck. I found that in mulpitle tests of just the crimps only, on equally prepped brass, same loads, that over crimping adversely effects accuracy on cast bullets.

Basicly you use a 30 cal expander just so your bullet fits into t mouth of the case, without cutting lead or the coating off. then seat to proper length, then as a seperate stage, crimp just enough to get a straight neck wall, without moving the bullet. Using good brass you should have plenty of neck tension to hold the bullet without a real turned in crimp.Trick is to preserve the bullet size as done before loading the cartridge.
I do the exact same process in my 358 MGP, AR-15s with 200 RCBS PCed at 2,500 fps So the recoil in your 308 with 165-170 is probably not as substantial as the light AR with 200 at the speed I push them at.

[LORH1]

Thanks to all for responding. To provide more detailed info, I am casting Lyman #311332, I have been crimping them but with a relatively light crimp. I am shooting them out of Savage 110 Trophy Hunter and Long Range Hunter. I am currently loading them into the rifle one at a time so recoil setback is not a concern. I have found best results via my MagnetoSpeed V.3 chronograph with IMR3031 at 34.91 grains at 2294 ft/ps @ 50 yds with about 1.25 MOA. I am powder coating and coating them with HBN. No lead fouling has been found...yet. I'm still experimenting and trying to cast more consistent bullets as to weight and form. They are currently ranging from 178grs. to 182grs. and look a tad rough as far as looks go. I am using Lyman #2 from Rotometals. Each time I make bullets they are getting better and better. I've made and shot about 150 so far. Hoping to get down to 3/4-1 MOA @ 50yds before I start shooting at 100 yards, expecting to get no worse than 1.5 MOA at 100 yds.

[gwpercle]

Cast rifle boolits are softer than J-word's ... to seat without damage the case neck must be flared or enlarged slightly so the cast boolit can be seated ... now you need to remove the flare ... a light roll crimp will do this ... the Word to remenber is
... L -I - G - H - T ... crimp ... Too much deforms case and/or boolit .
You are going to have to crimp a few to get it right ...once you get it right...keep that case to use as a "dummy" no powder , no primer and use it to set your dies in the future !
Load Safe,
Gary

[Wolfdog91]

I personally don't crimp anything

[Budzilla 19]

^^^^^^^^^this right here^^^^^^^^^^ don’t crimp any rifle rounds, seem to shoot well enough for my uses. Pistol rounds are all crimped, normally taper crimp. Just me though.
You do what you need to do. As usual, just my opinions.

[dverna]

If you crimp, one thing that may help accuracy is to maintain a consistent case OAL. It might not be as important with the Lee FCD, but seems to me that with a roll crimp, more or less crimp could cause variation in velocities.

[charlie b]

Try backing down the velocity to the 2000fps range. My best accuracy with a 1:10 twist .308 barrel is around 1900fps, with both my 210gn bore rider and 165gn XCB. Both do well powder coated when sized right. I would not bother with HBN. I've shot the 210gn at 2450fps with no issues (other than a loss in accuracy due to spin rate).

Casting is all dependent on temperature. Temp of the melt and the mold. Getting a good cadence is the key. Once you find that the weights will become more consistent.

[country gent]

If you decide to crimp, seat to depth first then crimp in a separate operation. The bullets crimp groove and case mouth may not line up when the die starts to crimp doing it in one step.

[high standard 40]

I'm like WolfDog, I don't crimp any bottleneck cartridges. The exception would be for tube fed rifles but I don't have any of those.

[Hick]

I'm like WolfDog, I don't crimp any bottleneck cartridges. The exception would be for tube fed rifles but I don't have any of those.

I don't even crimp for tube feed rifles (I have several). BUT, that said, I am very careful to use minimal flare for seating the bullets so that I have enough neck tension to handle the things that go on in the magazine.