7.62x40 WT

[Hawk]

I really like my muzzle brake, it's kinda heavy and long but sucks the recoil right out and pretty much eliminates muzzle rise, muzzle flash, and makes it plenty quiet enough to not need hearing protection at all. It was expensive though and required registration and permission from the BATFE.

Muzzle brakes do work, if you think you need one. I highly recommend watching two utoob videos by Jeremy S. where he tests 35 different brakes and rates them. Here's part one:

You guys always have the coolst links!

 

[Josh]

I plan on a brake for mine, not so much for recoil but for muzzle rise, mine does have some flip to it and makes it hard to spot hits. The 30-30 bullets will work and expand effectively if they will feed in your AR. I really like the Speer 130 gr FN for this cartridge if shooting "30-30 distance"

It looks like you are coming right along and are well on your way to enjoying one of the best 30 caliber cartridges for the AR platform.

 

[Hawk]

I really like my muzzle brake, it's kinda heavy and long but sucks the recoil right out and pretty much eliminates muzzle rise, muzzle flash, and makes it plenty quiet enough to not need hearing protection at all. It was expensive though and required registration and permission from the BATFE.

Muzzle brakes do work, if you think you need one. I highly recommend watching two utoob videos by Jeremy S. where he tests 35 different brakes and rates them. Here's part one:

I watched both videos and the muzzle flash test.

http://www.thetruthaboutguns.com/2015/06/jeremy-s/ar-15-flash-hider-shootout/

Some of those were wild, like the Doublestar Dragon. Nearly twice the Lux of a bare muzzle. Apparently designed to maximize the gasses and create a huge fireball. Crazy stuff!
This is going to be a mostly a hog gun, so I need something to reduce recoil and muzzle flash for night hunting.
This was exactly the information I needed. Now to find who makes them for .30 cal.
Thanks again!!

 

[Hawk]

I'm not going to hunt with the 30-30 bullets, just want to use them up to fire form the brass to mitigate the cost, since I have no other use for them. I don't mind loading them one at a time to fire form brass.
I also have some 165 grain Nosler Ballistic tips that I would like to use up in fire forming. Not really worried about blowing the gun up. More worried about sticking one in the bore.

 

[Josh]

I'm not going to hunt with the 30-30 bullets, just want to use them up to fire form the brass to mitigate the cost, since I have no other use for them. I don't mind loading them one at a time to fire form brass.
I also have some 165 grain Nosler Ballistic tips that I would like to use up in fire forming. Not really worried about blowing the gun up. More worried about sticking one in the bore.

Just use loads that run in the 3/4 throttle for the 300 BLK when forming your brass. Nothing will get stuck in the bore.

 

[fiver]

yep, you need some decent pressure to get those cases to fill out the chamber.

 

[Hawk]

Well, I pulled the trigger and ordered a barrel. getting a 16" Recon in stainless steel. Wanted the fluted barrel, but couldn't make myself spring for the extra $50.

I'm going to swap out the barrel on my Rock River for now, so I'll have something to play with.
Will get another rifle at the next big gun show in a couple of months.

 

[Josh]

You are well on your way, I hope you like yours as much as I like mine!

 

[Hawk]

I'm sure I will.

I love to tinker with stuff, as I'm sure all members of this forum do.

This will keep me busy for a while.

 

[Pistolero]

Nothing reduces muzzle flash like a suppressor...... Just sayin'.

How much can you really gain over a .300 BLK? Seems like for light bullets you may get a
slight gain in powder space -- maybe, but for heavies which I use for subsonic momentum in
my .300 BLK it doesn't seem like you get anything except 0.20" more brass covering up part
of the bullet. Tip has to be in the same place for 2.260 max LOA, so unless you have 110 gr
bullets seems like a .300 BLK and 7.62x40 will have the same powder space, pretty much
set by the bullet base and LOA, not much related to case length.

If we go down to a 110gr bullet aren't we back at the .30 Carbine round, pretty much?

Am I missing something here?

Bill

 

[Josh]

Nothing reduces muzzle flash like a suppressor...... Just sayin'.

How much can you really gain over a .300 BLK? Seems like for light bullets you may get a
slight gain in powder space -- maybe, but for heavies which I use for subsonic momentum in
my .300 BLK it doesn't seem like you get anything except 0.20" more brass covering up part
of the bullet. Tip has to be in the same place for 2.260 max LOA, so unless you have 110 gr
bullets seems like a .300 BLK and 7.62x40 will have the same powder space, pretty much
set by the bullet base and LOA, not much related to case length.

If we go down to a 110gr bullet aren't we back at the .30 Carbine round, pretty much?

Am I missing something here?

Bill

You are missing something here.

The 7.62x40 was never designed for subsonic use, it sports a 1-12 twist and the brass is optimized for supersonic loads. I have ran the 110-125 gr bullets into 2650 fps with accuracy.

It is a lot like the 7x57 and 7x57 Ackley, it gives enough of an improvement to step up performance by a good amount.

If you want the ultimate in versatility you can't beat a 300 BLK, but if you want a cartridge optimized for hunting, it is hard to beat the 7.62x40

 

[300BLK]

The A2 does a pretty fair job of suppressing the flash for not a lot of $$. I have a Yankee Hill Phantom on my 10.5", but its pretty large. I have a linear hider on one of my 16" and its advantage is in sending more noise downrange. I'm going to pull one of my devices and replace it with the Ares Armor Effin-A. The idea behind that device is to tune so that the muzzle remains flat and straight for quick follow up shots.

Those videos gave pretty good indications of what to expect from each of those devices. Everything is a compromise between flash, recoil, and noise. 5.56 ammo is ridiculous in the way of noise and flash compared to .223 and 300BLK.

 

[Pistolero]

OK, I had never heard of the cartridge before, looked up the dimesions and was wondering what
it was all about. Now I see. Interesting. Doesn't Remington make a .30 cal cartridge for the
AR platform? How do these two cartridges compare? Got the 300 BLK for suppressed use, never
have looked at any other .30 cals in the AR15, have an AR10 in .308, but it is bigger and heavier.

Bill

 

[Ian]

The .30 RAR is even more boutique than the 300 BLK, and is on the way out instead of in. Rounds count, magazine issues, not as good as a .308, not that much better than the 300 BLK, unique case, on and on. Not a bad cartridge in and of itself, but kind of pointless now that other things have been developed. The WT looks to me to have that little edge that the 300 BLK just doesn't quite get on the upper end of performance, albeit with lighter payload than the RAR can sling. If you need real power stick with an AR-10, Smith & Wesson makes one that's well under eight pounds and shoots very, very well. Incidentally, there are still no flies on the M1 Rifle.

Speaking of heavy, a 30-round Pmag stuffed with 230-grain subsonic 300 BLK cartridges weighs almost two pounds. That's more than a 20 round SR-25 Pmag stuffed with 165-grain soft points. Of course if you're hunting deer in most states a reduced-capacity magazine would have to be used, but for deer, I have nice bolt-action and lever-action rifles. My ARs are for war, for fun, and for varmints. YMMV.

 

[fiver]

a nice 130gr bullet [sierra] from the X40 would put it right in there with the old 30-30 loads.
only scoped and a bit more accurate.

that 2650 speed is 200 fps faster than the 300 BO with the 110's those Varmageddons would WOW,,, just,,,,, wow on a prairie Dog out to 200 yds.
i know what they do to a jack rabbits head at 2400 a P-dog would be pretty impressive.

 

[Josh]

a nice 130gr bullet [sierra] from the X40 would put it right in there with the old 30-30 loads.
only scoped and a bit more accurate.

that 2650 speed is 200 fps faster than the 300 BO with the 110's those Varmageddons would WOW,,, just,,,,, wow on a prairie Dog out to 200 yds.
i know what they do to a jack rabbits head at 2400 a P-dog would be pretty impressive.

Wait... you shoot condom bullets?!?!?!? Like from the factory? Well blow me down...

If I had Quickloads I would feel safe moving faster than what I am in my x40, problem is I don't want to be shooting round after round of 65-70K psi.

 

[fiver]

more like from my swaging dies.
but sometimes you gotta test theory's about what you make [and comparisons against known tested stuff to see how your doing]

i shot [AHEM] a couple of deer with my 25--06 last fall with some storeboughts comparing their effectiveness.

the nephew also was able to scratch down a couple of does with my homeswaged stuff, unfortunately he tried putting them both through bone at 40-50yds at @2700 fps so i didn't get the exact details of what i was trying to compare.
but i did learn 8"s of bone is about all my 30 cal bullets will push through before turning inside out completely.
so a couple of slight design changes are in order for next years foray in the 0-6 and a 308 to see how much better they perform.

 

[Hawk]

Rifle barrel came in today. I need to swap it out on my RRA rifle. Micro gas block won't be in for a few days.
Got a Lee 312-155-R and a sizing die coming in tomorrow, so I can cast some bullets to fire form brass. Decided I didn't want to use j-words for fire forming.
I'm going to try to powder coat some and see if they will chamber. We'll see.
I need to pound cast the chamber, but have never done it before. Not sure I'm ready to try that just yet and have no fire formed brass anyway.

 

[Josh]

The 312-155 will not chamber in the 7.62x40, the throat is very short and K-31ish. I wish it would as it is the perfect OAL when seated to the crimp groove

 

[300BLK]

a throating reamer will solve that issue