Which COAL to use?

[OkieMike]

Doing a load workup for my .308 gasser...

LC 07 brass, Hornady 150 FMJBT, and SW Match rifle powder.

SW load data says 2.75 OAL, but I think they're using Jagemann brass.

Hornady says 2.700 OAL which would put the case mouth in the cannelure.

Should I use the Hornady OAL and crimp in the cannelure? Or go with the longer length and crimp wherever?

I'm starting at the bottom and working up in .4 gr increments. Plan to keep an eye on things as I proceed.

Any suggestions/advice appreciated.

Mike

 

[DownhillFromHere]

Since you're loading blaster ammo (e.g., 150gr FMJBT with cannelure), I'd seat the bullet with case mouth to the cannelure and be done.

As far as crimping is concerned: I haven't loaded .308 for gas guns yet - only .223. I don't crimp .223 ammo, whether it be for gas or bolt rifle, and it appears from reading here that few people do. Of course, .308 has a lot more recoil so I cannot say whether crimping ammo for a gas gun is necessary or advisable.

 

[r.tenorio671]

....it's well worth it to get an Hornady OAL gauge and modified case(s) so you can get measurements SPECIFIC to YOUR barrel chamber, check this vid out nd by the way, you can use the straight model in AR's, much easier & preferred than the curved model. Even better when used in conjunction with comparators to get the measurement of the ogive, which is more consistent than the tip of the bullet(s)...every brand of bullet (type, weight, etc.) differs and "fit" differently in individual barrel chambers..

 

[JMGlasgow]

I've loaded thousands of rounds of that bullet for my M1A's. I seat the bullet to the cannelure and move on. I've never crimped those bullets either and haven't had an issue with the bullet moving in the case.

 

[nn8734]

Doing a load workup for my .308 gasser...

LC 07 brass, Hornady 150 FMJBT, and SW Match rifle powder.

SW load data says 2.75 OAL, but I think they're using Jagemann brass.

Hornady says 2.700 OAL which would put the case mouth in the cannelure.

Should I use the Hornady OAL and crimp in the cannelure? Or go with the longer length and crimp wherever?

I'm starting at the bottom and working up in .4 gr increments. Plan to keep an eye on things as I proceed.

Any suggestions/advice appreciated.

Mike

Crimping isn’t necessary. Start with 2.700 oal and make seating depth adjustments as needed. More than likely 2.700 will suffice.

Here’s how I determined seating depth with my 556 77smk load. I just looked at how far Black hills seats the bullet into the cannelure and replicated it. Haven’t needed to do anything else seating depth wise.

 

[OkieMike]

....it's well worth it to get an Hornady OAL gauge and modified case(s) so you can get measurements SPECIFIC to YOUR barrel chamber, check this vid out nd by the way, you can use the straight model in AR's, much easier & preferred than the curved model. Even better when used in conjunction with comparators to get the measurement of the ogive, which is more consistent than the tip of the bullet(s)...every brand of bullet (type, weight, etc.) differs and "fit" differently in individual barrel chambers..

I've got one. Use it all the time. But I'm pretty much limited to mag length in this gun.

Mike

 

[Doom]

I've got one. Use it all the time. But I'm pretty much limited to mag length in this gun.

Mike

Use the 2.700 if or 2.750 it really doesn't matter. That bullet has the cannelure set for 30-06. From an accuracy standpoint you should be able to get good accuracy from that length. A word of advice. You will see flyers with this bullet. I have used it in 308 Bolt gun and every so often you throw one. Usually no more than 1 MOA but just be prepared.

 

[OkieMike]

Thanks for the help.

This is an off the shelf gun that I've been fighting with for a couple years. Overgassed bad... stovepiped quite a bit and threw brass to about 1:30...

Put a new trigger in, accuracy got a tad bit better but still bad. Put tungsten buffer weights in... Not much improvement. Last step before I sold it was an adjustable gas block. Got a Seekins Precision installed and tuned. Groups tightened up, stovepipes ceased and brass goes to 3:30/4:00

With the AGB it was doing .75 to 1 moa with PMC 147 fmj's... So I figured I would tune some handloads and see how tight I can get it while still being fairly practical and inexpensive.

If I can keep it 1 moa or better with cheaper components, I'll call it good.

It'll be fun to tune and tinker with and hopefully keep me off the streets.

Mike