.300BLK & copper plated bullets Part II

[AntiHippie]

So, I got these Xtreme 150 grain flat points running just fine with Lil Gun. Cycling fine at 14 grains, probably at 12 grains but who knows because it turns out Militec sucks donkey dong for corrosion protection and my expensive as hell Syrac adjustable gas block rusted over a few days because of dumbass me thinking Militec was way better than Breakfree.

Had to take the upper down to loosen up the setscrew on the gas block without costing myself lots of dinero, but before I even got to the taking the hand guard off part, noticed LOTS of copper. Ever grind up 4 pennies and mix them with Vaseline and use them to lubricate your gun? I haven't, but I'm pretty sure that's about what it would look like. Tail end of the bolt looked copper coated on one side, had actual copper deposits on it, flecks everywhere in the upper, forward face of the buffer looked pretty special, too.

So my question to NES:

-Too much crimp, which it seems to my simple and fairly inexperienced mind I need some of to keep the bullets from falling out or setting back?

or

-Too fast? Still haven;t bought a chrono (I know) - but I haven't been driving these bullets TOO hot, according to extrapolated data.

or

-Dumbass is chasing unicorns trying to make .300BLK plinking rounds with .30-30 bullets and needs to quit now.''

or

-Something simpler?

 

[AyeR15]

So, I got these Xtreme 150 grain flat points running just fine with Lil Gun. Cycling fine at 14 grains, probably at 12 grains but who knows because it turns out Militec sucks donkey dong for corrosion protection and my expensive as hell Syrac adjustable gas block rusted over a few days because of dumbass me thinking Militec was way better than Breakfree.

Had to take the upper down to loosen up the setscrew on the gas block without costing myself lots of dinero, but before I even got to the taking the hand guard off part, noticed LOTS of copper. Ever grind up 4 pennies and mix them with Vaseline and use them to lubricate your gun? I haven't, but I'm pretty sure that's about what it would look like. Tail end of the bolt looked copper coated on one side, had actual copper deposits on it, flecks everywhere in the upper, forward face of the buffer looked pretty special, too.

So my question to NES:

-Too much crimp, which it seems to my simple and fairly inexperienced mind I need some of to keep the bullets from falling out or setting back?

or

-Too fast? Still haven;t bought a chrono (I know) - but I haven't been driving these bullets TOO hot, according to extrapolated data.

or

-Dumbass is chasing unicorns trying to make .300BLK plinking rounds with .30-30 bullets and needs to quit now.''

or

-Something simpler?

Im guessing you are pushing these too fast. What does the listed data suggest for FPS? I am interested to see how this works out for you, I have the exact same bullets siting at home for my dads 300 but haven't had time to load/chrono them. I was always leery about plated bullets in a 300BLK rifle.

 

[Rugerfan]

As said, plated bullets have velocity restrictions, heed them. Crimp as little as possible and still make it through chambering w/o setback.

This could also be caused during feeding into the chamber. Cycle a few rounds through, unfired, and check the bullets for damage. Finding the material on the bolt face behind the brass makes me think this is a possibility. Inspect the bore for any copper remnants.

 

[gerrycaruso]

I load the same bullet in .30/30 and keep the velocity down to about 1600 fps. I think plated bullets are supposed to be loaded to lead bullet velocity. If you can't find the answer online, call xtreme.

 

[AyeR15]

I load the same bullet in .30/30 and keep the velocity down to about 1600 fps. I think plated bullets are supposed to be loaded to lead bullet velocity. If you can't find the answer online, call xtreme.

Pretty much all plated bullets are rec. to stay under 1500fps. Lately company's are selling "Thickly Plated" to suprass that fps mark. I load all my plated bullets to FMJ specs (powerbond, Xtreme, RMR also rec. it) but rarely push them over 1200 fps

 

[AntiHippie]

As said, plated bullets have velocity restrictions, heed them. Crimp as little as possible and still make it through chambering w/o setback.

This could also be caused during feeding into the chamber. Cycle a few rounds through, unfired, and check the bullets for damage. Finding the material on the bolt face behind the brass makes me think this is a possibility. Inspect the bore for any copper remnants.

Wasn't so much the bolt face - it was the tail end of the bolt, and all over the front of the buffer. I'll try to post photos later.

 

[EddieCoyle]

Wasn't so much the bolt face - it was the tail end of the bolt, and all over the front of the buffer. I'll try to post photos later.

The only way it's getting back there is through the gas tube. Are you sure it's rust that's messing up your gas block?

What kind of barrel? Usually if you're getting a lot of copper, the barrel is rough. What happens with jacketed bullets? How is the accuracy with the plated bullets?

Also, why are you crimping? Because the bullets have a cannelure?

 

[AntiHippie]

Assumed it was rust because I noticed flecks of rust on the barrel and side of the gas block that weren't there a week before. I dropped some Break Free on the setscrew and jiggled it until it loosened right up. Aero Precision 8" Melonited barrel. Jacketed bullets seem to run just fine.

Accuracy isn't great with the plated bullets, not horrendous, either. 50 yards everything's inside 10" shooting offhand, not rested, so I can't put any confidence int the performance of the ammo yet - I'm not exactly a sharpshooter. Can't imagine it's going to be tack driving, though.

I lightly crimped them because they'd set back with moderate thumb pressure, figured getting racked into an AR chamber would bury them in the case.

 

[EddieCoyle]

Wow. I find it unusual that the rounds would set back with simple thumb pressure. My .300 BLK won't set back no matter how hard I push on it, and I don't crimp. Did you happen to measure the bullets to see if the diameter is right? Also, which brand of dies are you using?

My point about the gas block is that in order for you to get flecks of copper on the back of the bolt, the copper had to go through the barrel, then the gas block, and then the gas tube. Unless I'm missing something, there's really no other way for that stuff to get back there. If you get the gas block off, I'd be curious to see what you find in there and in the gas port in the barrel.

 

[AntiHippie]

Lee dies - will probably be changing over to Hornady soon, as I work with a guy looking to sell a brand new set for short money. I'll measure the bullets today and see whee they average out at.

Photos:





Edit:

The plated bullets measured .308 on the nose. At least the ten I randomly pulled from the box all were. Just for kicks and grins, I dropped the expander out of the die and measured that - .3065. Measured a few pieces of random prepped brass I had and they were all about .3065 ID.

I've also noticed when loading Hornady 150 BTSP's they'll almost fall to the cannelure if I seat them longer (id est, cannelure exposed just above the case mouth). Does kind of seem to me like there should be more neck tension. Any idea what the OD of the expander should be, or the ID of the case neck? I see on the SAAMI spec that the bullet diameter is .309 +0 -.003, so to my simple mind, the case mouth, at .3065, is already towards the narrow end of the range?

 

[AntiHippie]

Update: If I size again after trimming, there's enough neck tension I can't set the bullet back even pushing it against a workbench. Also, once fired (twice, really, since it was made from on e fired 5.56) was the same. Plenty of neck tension, no crimp necessary.

Best I can figure, trimming with the little Lee cutter was knocking the case mouth oversize, or it just needed a couple trips into the sizing die. Or both.


Made up a couple dozen rounds with no crimp at all, will see if the copper returns.

 

[AntiHippie]

Still some copper in the same places. Not so bad as before.

Suppose I really need chronograph.

 

[55_grain]

Looks like you've solved your own problem.
If you still have some of the crimped rounds, take a few apart to see if you're cutting through the plating...a kinetic (hammer) tool is really short $ if you don't have one.

 

[Savage-06]

If your pushing them too fast (i.e higher chamber presures) with a pistol length gas system. The round may not be in battery long enough and causing the deposits that way just my .02 I am new to reloading and .300 blk