u/Tmoncmm

I have a slight dilemma. I was given a little over 200 pieces of primed, virgin .300 blk brass. The problem is, the shoulder measures on average .006 longer than my new Starline brass. As I suspected, it’s difficult to chamber and extract so it’s obviously out of spec. I’m absolutely sure it’s virgin brass… clean as a whistle, no sizing die marks and no other scratches or imperfections. It’s just slightly out of spec. Running it through my sizing die puts it back to where it needs to be and all is well.

Here’s the challenge… how would you go about sizing all this brass? The way I see it I’ve got a couple options…

1. Lube by hand and size one at a time on my turret press.

2. Place cases upside-down on bench or in loading block to help prevent lube from entering the inside of the case then spray with Dillon lube and size on my progressive.

Then..

1. Wipe lube off by hand with alcohol and paper towels like I do for small batches. (Would suck, but is probably safest)

2. Dry tumble in corn cob for about 45 minutes like I do for big batches. (Easiest, but worried about contaminating / f’ing up primers)

3. Spray lube, size, load and then dry tumble loaded rounds in corn cob. (Worried about powder sticking to lube that will inevitably make it into some of the necks, never tumbled loaded cartridges before.)

If you were in my shoes, what would you do?

I see this is one of the more common posts here and I hate to add yet another, but I get why. This cartridge has such a super wide range of different hosts and applications that the best choice for a can really depends on one’s specific weapon, ammo and intentions.

That said, I’m new to the cartridge and decided I wanted to rebuild one of my 5.56 ARs into a .300BLK SBR dedicated to heavy, subsonic suppressed shooting.

Weapon details..

Faxon 7.5” 1:5 match barrel
Standard low profile gas block and tube
JP-SCS with lighter (white) spring installed
Standard DD BCG

Ammo details (hand loads)..

Barry’s 220gr plated @ 2.150
8.5gr N110
Starline brass
CCI 41
990FPS Avg (1000FPS max rated velocity for this bullet in a 1:5 twist barrel)

Currently using my omega 300 with Plan-A and flat end cap because it’s my only 30 cal can. I got the can for use on my precision rifle with Recoil-X brake, but it’s on this build right now as a test.

Performance details..

Cycles reliably and locks the bolt back with this load. 8.3gr of N110 would cycle reliably but only locked the bolt back about 1/3 of the time so my current load is obviously right on the line of reliable operation.

It will not cycle reliably without the suppressor.

Sound performance is better than I expected, but probably could be significantly improved. It’s quiet enough that I’ll shoot without ears for short sessions, but I wouldn’t do it all day.

Almost no gas to the face. I expected less than my previous load with CFE Black (gassed out after 5 rounds), but not nearly this good. Not surprising I suppose as this load is probably burning over 95% of the powder before muzzle exit.

What I’m looking for..

First and foremost is functionality. It must work reliably. Keep in mind that since I hand load, I can try different powders to tune somewhat for that, but I’d rather not deviate too much from my current load as it currently works and performs well. Given that the weapon will not cycle without the can, a low back pressure design seems off the table.

Second is sound performance. I’m looking for the quietest can I can get that still functions and is within reason for length and weight.

Third is length. It’s a short build for a reason and I rather not put a foot long can on the end of it. That said, I wouldn’t be opposed to going longer than the omega 300. I would happily consider a can that was ~9” if it did what I wanted it to do.

Weight is fourth. See above.

Mount..

I’m currently using Plan-A because I like the low profile and the taper mount, but it’s not a deal breaker if the new can isn’t compatible. It will get mounted however it does.

Intended use..

This can will be dedicated to this gun and may see use on future .300 blk builds if I ever decide to go that route. It will mostly be used for shooting at steel with a moderate to high firing schedule.

Budget..

I’ll pay what it costs.

Current considerations..

I’ve been hearing that the Hydrogen-L, CGS Hyperion, Liberty Mach-L and CAT JL are among the best, but I’d like to hear opinions based on my specific application.

Don’t really need help, just speaking out loud on my experience and interested in other’s views.

My MPA Vanquish came with the BnA trigger and I’m not really sure I like it. It was set at 12oz by MPA and felt a little mushy to me so I adjusted the pull weight to about 1Lb 3oz and adjusted the sear engagement per the manual. I also readjusted the trigger hanger to make sure it was optimized and free from cock/decock on close. I like it better now, but it still doesn’t have what I would call a clean break. It’s not mushy and there’s no detectable creep, but it doesn’t have the snapping a toothpick break like the TT has. I’m also not a fan of the over travel. The trigger definitely isn’t holding my back though. That rifle consistently produces excellent results with a variety of bullets so it’s hard to justify replacing it.

I’ve considered switching it out for a TT, but I have a weird mental hangup about ditching a trigger that can be disassembled and serviced in addition to adjustable sear engagement (two features I feel like are really cool) for one that can’t be and doesn’t have it. That’s just a weird me thing. It’s the same reason I won’t put an optic on my VP9. I really like the nice suppressor hight, tritium sights and it seems a shame to negate them with an optic.

Thoughts?

I just put together a new SBR in .300 Blk. This is my first experience with this cartridge.

I’m running a Faxon match 7.5” 1:5 with faxon low profile gas block and JP silencer capture spring. Standard BCG. This will be a dedicated suppressed, heavy subsonic rifle mostly for plinking fun. I have no interest in supersonic loads with this rig.

So far, I’m really happy with it. My first loads with Barry’s 220gr plated @ 2.150, once fired range brass, CCI 41 and 12gr of CFE BLK produced 100% reliable cycling and bolt lock back. Average velocity of 976 FPS with acceptable precision and an SD of about 11 over 35 rounds. I’m currently running an Omega 300 direct thread. The load cycles with and without the suppressor and surprisingly, I felt no gas blowback at all. It’s also worth mentioning that the rifle also cycled reliably with my starting load of 11gr, but the average velocity was only 875 FPS and ejection was a little weak, but the bolt did lock back on an empty mag.

My ultimate goal is to run the quietest subsonic load I can at a velocity close to, but not to exceed 1000 FPS (per Barry’s max rated velocity for this bullet in a 1:5) that will still reliably cycle the action. Ultimately, I will get another suppressor dedicated to this rifle, but that’s a decision for later on. There isn’t anything wrong with the Omega 300, but I’m borrowing this one from my precision rifle for the time being.

I’ve read a lot of people say that N110 and N120 are great for heavy subsonic loads. I’m leaning toward N110 as a first try because it should be fast enough to burn completely in that short barrel and in my experience, this is best for suppressor use if you’re trying to stay quiet.

My question is, does anyone use N110 with a similar length barrel and components with good results? My concern of corse is that it will be too fast to reliably cycle the action.