Ed,
I have 25# bags of shot too.
A look at your 36" barreled NEF will be interesting.

The 24"-fat-barreled NEF with laminate stock is a wee bit muzzle light with the scope and slip-on pad I have on it, at 11.5#.

Adding a big, fat muzzle brake and some lead or mercury to the butt ought to balance it.

Rob mentioned an internal muzzle brake system as an add-on to the NEF. Is this a sleeve that screws over the barrel?
A picture of that would be intersting too.

Still looking for the sizing die from Lee.
I have some Lyman #2 Darwins that need sizing to .730".

Will crack Mach 1 with those in the RMC cases.
Maybe the 65-grain charge of IMR-4227 will do it with the Darwin in the RMC brass. Will start there and work up ... eventually Mach 2 with brass slugs and Rob's brass ... and more weight and a muzzle brake on the NEF ...

The full custom 12GaFH ought to have a pair of shock absorbers in the butt.

Mach 1, about 1125 fps,
Mach 2, about 2250 fps,
Plenty fast for a 12-Gauge slug.

I think this F/A-18 Hornet cruised by the AC and a sailor snapped this pic at about Mach 1 (767 mph, 1235 km/h). Water vapor condensing into cloud in the low pressure trailing causes the cloud-like flare:

Ed and Rob,
What do you think about this muzzle brake from Brownells, for 50BMG, made by Vais, stainless, 4" long, 1.5" diameter, 13.4 ounce weight, 1"x24tpi threaded:


The NEF muzzle diameter is about 1.075" at the end of the taper down, bigger everywhere else on the barrel.

That brake could be bored out to pass a 12GaFH slug, or a piece of 12ga barrel from PAC-NOR could be machined into something similar.

That brake bored out might work, it sure will thread on the
NEF barrel. Brett in MN is putting a coil spring hydraulic deal
in the butt of his Savage to tame recoil.
Tested Chrono with couple different little bore factory stuff
and it is a 100 ft high compared to their specs. Maybe it has
been shaken up too many times by stuff hitting the wires.
Got knocked off bench couple times.
For add on bbl on NEF used the back half of savage rifled bbl
I had extra. Has same twist and same number of rifling.
Put it on with a sleeve and lined the rifling up. Still
plenty heavy at 1.00" at new muxzzle.Ed

Make the exit hole about .050" bigger than bullet diameter?
.730" + .050" = .780"

Maybe a standard 3/4" hole, .750", only .020" bigger hole than bullet, and a recessed crown to protect that match grade slug accuracy?

Maybe I ought get some precision gunsmith help, rather than do this with my $99 drill press and hand tools. Where is that 1"x24tpi die ...

That muzzle brake would play hell with wads, sabots, filler, eh?
Strictly for hellacious loads with cases full of slow powder and no fillers?
Looks like I might need a second NEF with all the bells and whistles.

Muzzle brake hole can be just about anything over bullet size but anything over about 0.040" and you start loosing braking efficiency. I like a little "play" so I keep my brakes 0.035"-0.045" over bullet size and I bore out the brake chamber to the same dimension required for internal threading of what ever calibe I happen to be braking.

I've read that external brakes aren't recommended for use with sabots in rifles....get a sabot crossways in the brake bore and you can cause all kinds of jumping up and down...you could get away with nitro cards is suspect if you check the brake each time....

I wouldn't use an external brake on any shotgun barrel even though the "Original shotgun brake" the Cutts Compensator seemed to work OK. But an internal brake like used on Mossy barrels or the Vang? thing, Magnaporting etc would be OK...I haven't seen or heard of any problems using these types of compensators with sabots, plastic wads or other wads.

The external thread on brakes are sure easier to install though...and there are many different brakes to choose from...the best and most efficient copy tank compensators. Just two big holes on each side. I made a couple to try out but they were just too UGLY and I used 30 dollar jobies from Harralls Precision...He doesn't make them over 3/4" od tho'.

Rob and Ed probably are more knowledgeable on this tho'...I just know about rifle brakes.

Luck on your projects.

FOOBAR,
You speak straight.
Good place to hang the muzzle hole thinking cap: plus .035" to .045"

The proportionally huge slugs of .730" should make that tight enough, compared to .308" bullets, etc.

Lessee: .730" + .045" = .775" max for muzzle hole of brake.

That is 10-gauge bore. Like the 12-gauge Mossberg 835 Ulti-Mag smoothbore.
One could cut off the chamber end of an Ulti-Mag smoothbore barrel (has 1.190" diameter for a 4" parallel Knoxform shank), female thread it to fit the male-threaded muzzle of the NEF, drill holes in the sides of it and whack it off at about 5 to 6 inches length, so as to get well past the forcing cone of the chamber and into a straight-sided segment of .775" diameter bore for the crown of the muzzle brake.
Voila! 12GaFH compensator!

The Vais brake from Brownells would look better.

Of course for any regular shotshell loads with shot cups/wads, sabots, etc., the brake might get damaged, explode at the muzzle, etc.
However the brake would be easy to remove and replace with a thread-protector muzzle cap.

So much of shooting we do is with wads.
How about making a screw on section about
6" long, exact id bore size, with magneport
type smaller holes on the top 60 degrees.
About two rows of 10 holes, maybe third row
straight up. Most wads/cards will seal in it
so length will give little more velocity.Ed

My thought is to simply bore out the NEF muzzel about .025 for 1.5 inches and drill lots of 3/16 holes around the muzzel using a indexing head. I did this to my NYATI and a few other guns and it worked amazingly well. You guys are absolutely right about not shooting wads or sabots through a external with expansion chambers like the Vias brake. A Big No No. You can shoot them through a internal brake like I've described though.
Basically the higher the gas pressure the better a muzzel brake works. I see no problem with the Vias brake and it will cut felt recoil significantly just cant be used with sabots or wads. BTW I worked with George Vias to design that brake and it was first fitted to my .600RLG based on the .50BMG case. Adding some extra weight to the NEF muzzel may actually be a good idea as is a longer barrel period. My Quick load calculations indicate that Ed is right on the mark and you really need a much longer barrel like 32 inches when your restricted to slower powders like H50BMG in the NEF. My Borchardt can use much faster powders at much higher pressures, so 26 inch barrels are much more efficient.-Rob

quote:

Originally posted by hubel458:
So much of shooting we do is with wads.
How about making a screw on section about
6" long, exact id bore size, with magneport
type smaller holes on the top 60 degrees.
About two rows of 10 holes, maybe third row
straight up. Most wads/cards will seal in it
so length will give little more velocity.Ed

Ed,
Chalk up another good cat skinning technique.
That is very similar to the porting on the Mossberg 835 Ulti-Mag full-rifled bore, and the smoothbore.
The holes directly into either the rifling or the smoothbore do not cause any problems with any wads or sabots. I think they are about 3/16" diameter two rows of 4 holes on either side of the top, jah, about 60 degrees apart, total of 16 holes IIRC.

quote:

Originally posted by Robgunbuilder:
My thought is to simply bore out the NEF muzzel about .025 for 1.5 inches and drill lots of 3/16 holes around the muzzel using a indexing head. I did this to my NYATI and a few other guns and it worked amazingly well. You guys are absolutely right about not shooting wads or sabots through a external with expansion chambers like the Vias brake. A Big No No. You can shoot them through a internal brake like I've described though.
Basically the higher the gas pressure the better a muzzel brake works. I see no problem with the Vias brake and it will cut felt recoil significantly just cant be used with sabots or wads. BTW I worked with George Vias to design that brake and it was first fitted to my .600RLG based on the .50BMG case. Adding some extra weight to the NEF muzzel may actually be a good idea as is a longer barrel period. My Quick load calculations indicate that Ed is right on the mark and you really need a much longer barrel like 32 inches when your restricted to slower powders like H50BMG in the NEF. My Borchardt can use much faster powders at much higher pressures, so 26 inch barrels are much more efficient.-Rob

Rob,
Thanks for explanation of your internal muzzle brake. My .458/338 Lapua Mag is done that way too, with the holes drilled through the front sight barrel band.

So you think plus .025" is good enough, eh?

Does anyone know the minor diameter of the threads on that Vais 50BMG brake? Spec is 1"-24tpi.

Maybe the expansion chamber inside that Vais brake is drilled to the minor diameter or only slightly smaller, and is already big enough to pass a .729"-.730" bullet?

If so, then all that needs to be done to it is to enlarge the exit hole at the muzzle to .755"-.775"?

External thread - minor diameter is .9491" on the external thread...that's for 1"-24 class 2A.

If I was putting internal brake on say my
extension barrel of NEf,use size/spacing that
I got on the Mossy 695 slug gun barrel I took
off. 1/8" holes -- 1/4" apart. One row
of 8-10 straight up, and a row on each side
of that 30 degrees right/left. Total of
24 -30 holes will do. And small 1/8" won't
bother anything going past them even the
big long slug. I've seen other slug guns
with 1/8" holes work great.As long as your
putting something on may as well get
little velocity boost.Ed

Rob said it right on...the holes relieve and redirect the gas jet...the more gas the more recoil reduction...the holes don't do much for relieving the recoil caused by the slug/bullet.

All good ideas about how to make the brake...not sure I would chop up a good shotgun barrel tho'...there are lots of good steels available including aluminum that would be cheaper.

One thing I want to try and haven't gotten around to it yet is making a short Cutts style of comp without the front restriction to see if it would work with fiber wads and plastic sleeved wads...NOT sabots. Still thinking on this one.

No question about longer barrels contributing to the efficiency of the load. Eds idea of an add-on internal brakde is a good one and so is Robs...which was my initial idea.

My ported Mossberg rifled barrel doesn't have any bored out section in front...the rifling continues to the end of the barrel.

There are two rows of holes on each side of the barrel at roughly 30°, 1" long by ~0.325" wide, 4 holes per row, 16 holes total, ~0.125" dia, drilled starting ~3.40" from the end of the muzzle. That's roughly 0.0122 sq in of area.

Crunching some numbers using my Mossy at 7.5 lbs, 750 payload, Dixie slug and wad stack, at 1300 f/s, 36 gr powder and 46% brake efficiency gave 46 ft/lbs recoil with brake and 55 ft/lbs without brake. Running a check with another recoil program gave the same 55 ft/lbs without a brake.

Something strange was going on with the program/calculations tho'...the higher I went with the bore/vent area ratio the higher the recoil number went...basically opposite of what they should have been doing. I was using a program called RECOIL.EXE I picked off of Varmint Al's site. It was saying the more holes you drilled the less efficiency and the more recoil even though the recoil was less than without the brake holes. This doesn't compute and I need to chase down the reason.

Anyone got an idea...???

Went back to Varmint Al's site and re-ran the numbers using his newer program and the numbers started acting right again.

Basically it's saying that with my low velocity load and light powder charge their isn't much recoil reduction due to the small volume of gas...wellll DUH...sometimes I get so wrapped up in one thing the obvious just blows by me.

Anyway a brake will work much better at the higher velocities and powder amounts that you guys are working with.

quote:

Originally posted by Macifej:
External thread - minor diameter is .9491" on the external thread...that's for 1"-24 class 2A.

Thanks, Mac.
If the major diameter is truly 1.000" (or .990"?)
That makes for a thread projection of 1.29 mm, just to mix units.

1.0000" - .9491" = .0509" = 1.29 mm
0.9900" - .9491" = .0409" = 1.04 mm

Mighty fine thread for 1" pipe.

I ordered one of the Vais brakes for 50BMG from Brownells.

My Ruger No.1 500A2 has a 1" muzzle at 27" and could use one of those to better effect than what it has now, if I don't end up using it on the NEF.

Rob,
Don't sweat the collet enlargement for me.
I ordered some more collets in 1/64" increments:
3/4 = 48/64 = .750"
49/64 = .765625"
25/32 = 50/64 = 0.78125"
51/64 = 0.796875"
13/16 = 52/64 = 0.8125"

Maybe that array will be able to adequately squeeze either your cases OR the RMC cases (with neck/casemouth annealing).

Yes, with the no-wad, slow-powder, lots-of-powder loads, a muzzle brake on the NEF is indicated, according to my shoulder.

The 1000-grain brass slugs will be good for getting velocity up, trajectory flattened, and recoil reduced, compared to the 1400-grainers.
"Them, they were giants!"

Macifej is supplying a brass FN SHARRC slug of .729"/1000-grain variety ... get your orders in for Super Precision ... don't get left out in the ballistic tinkering cold!
They make nice paper weights too!
A clever alternate use for when the Democrats require serial numbers on every bullet and cartridge case!

Rob has the .729/1080-grain Brass Darwin Beer Keg too.
Too bad the Name "Foster Slug" has already been taken.

quote:

If the major diameter is truly 1.000" (or .990"?)

Major diameter is .9987 - .9915

Pitch diameter is .9716 - .9674

Tolerances, tolerances, close enough, thank you.
24tpi/25.4mmpi = 0.9449 threads per millimeter, each thread sticking out about a millimeter, I can visualize it now.

Put the Mossberg cantilever scope base in a vise with some aluminum blocks, then used the barrel as a lever to put some elevation and windage on the Ulti-Mag. I should have plenty of scope adjustment now!

Those 30:1 1401-grain "Triple Foster" Darwins at 1000 fps should be dead-on in the Mossy also now.

Gotta pester Lee about what happen to my .730" custom sizing die.

The Darwins in Linotype might weigh 1333 grains and break the sound barrier even in the Mossy.

Assume pure lead weight of Darwin = 1438 grains
x 0.9271 Linotype/Lead (weight ratio)
= 1333 grains Linotype

Say RIP!!

What does that flying lead beer keg sound like going down range...?? Any comments from bystanders...??

Subsonic: WHOMP-WHOOSH-WHUMP

Hoping for supersonic soon: CRACK-SPLAT

A 1333-grain Linotype "Darwin" will be 3.047 ounces.
That is still a "Triple Foster" slug.
.730-cal/1333-grain SD = .357

NEF got reamed out today and is now in the indexing head getting its brake drilled. Firing pin mods and lead/epoxy in the stock tomorrow and maybe a test firing tuesday. I'll post some pics of the process. BTW it took longer to get the barrel out of the action then to ream it. CNC Rims fit perfectly and the adjustable headspace capability is a nice feature. The One RMS case I tried seemed to need more sizing though. I think my cases are well worth the freight.
Up-Date- Muzzel brake is finmished and gun reassembled. Note: I set the gun for zero headspace by adjusting the rim depth and tried a few .50 BMG primed cases. The NEF fired them with no issues. I think it comes from the factory with pretty generous headspace for std 12Ga shells and shotgun primers are easier to light off than .50BMG. However, if you set the .50BMG primers only .002 below the case head ( while making sure they are armed properly- a large flatened area of the primer) then by setting the headspace to zero on closing the action, it will light off every time.
Finally, those RMC cases will chamber but they need some serious sizing particularily at the base. I THINK A POUND DIE IS THE TICKET FOR THEM, BUT WILL THE RIMS SURVIVE AND FOR HOW LONG?
-Rob

Cool! Keep us posted.

Hi Ed, an every1 else. Ed, I have an img of a new barrel I want Pac-nor to make, can you cast an eye at it an give it the old 1's over. Thx

The 12GAFH sickness is spreading like the Spanish Flu...!!

Should the barrel twist be upsidedown for Australia

quote:

Originally posted by boom stick:
Should the barrel twist be upsidedown for Australia

Nah...the rotation is opposite though...

I got a handful of 10 gauge brass.

Should I save these for the 10GFH or cut off the rims, add an extractor groove and neck to 12 gauge to work in the 210??? 12 gauge Nyati of sorts...

That's Pinata' brass Boomer...not good for anything but what it was made for.....don't waste you time. Rune em through a tumbler and put em in your collection for later use.....

If you need em Maytag'd send em down to me and all run em through my big tumbler while I'm frying brain cells here in AutoCad land.

Well it should be good for under 30K psi in a tight chamber...

12 Gauge Express???

quote:

Originally posted by boom stick:
Well it should be good for under 30K psi in a tight chamber...

12 Gauge Express???

NO!! They were designed for 12,000 PSI Boss...there's no metal in the base and the stuff is paper thin in the body.

Boomstick- That stuff is real weak brass and as macifej said good for 12K PSI max. Useless even for a medium pressure gun. Dont waste your time.
Gibs- Thats a real long tube youve got there! It should make damn near 1800fps with my H50BMG load or way more( like 2400 fps) in a savage 210 which I think you guys have pushed to 45Kpsi or more. My Borchardt has a 2" breech but my tube is only 26 inches long as it was designed for faster powders.-Rob

Rob - Great work,Glad you got primers going ok.
The next powder up Rob in speed for our big
primer long case, stick powder, good for NEF,
is Hodgdon Retumbo.

Gib --That barrel will long enough. It won't
have to be that heavy. Mine on Savages, one for
the 12ga FH and other my 700 H 3.25 belted, are
1.375" & 1.350" respectively, breach section and
1.200" & 1.150" at the muzzle.Ed

Thx Ed, Rob
Ed - The Breach is 1.375", the 2"section is for the Integral Muzzle Break/Magnum Porting with Bore an rifling right the way through to the very end of the brake. No overbore. I think I'll change the chamber to 3.85" and go the whole hog for a true SGFH.

Rob - I dont intend to shoot anything heavier than 300/350Gr progy. It will either be a AL/Copper Sabot of some kind or a full bore bullet made ultra light from AL with a small expander tipped setup. All from a 3.5"/3.85" RMC brass casing using ADI powder AR2205 or AR2207. least ways thats the plan!

Rob...you've got mail.

Range Report!- The H&R/NEF fired its first .729 1085 gr Darwins today and survived! First load was 210gr of H50BMG and recoil with the integral brake was about like a hot 300wby. Not bad at all! Then came the Big Kahuna 240 grs of H50BMG and it pretty much duplicated the felt recoil of a 8.5lb Lott with no brake! This was a proof load calculated to go about 27KPSI.About 20 grs over where it is optimized for the gun. This is a 100% case capacity load. You really knew you just lit off a serious round. Without the muzzel brake I dont think I'd want to shoot too many of these though. Gun was totally controlable though and hit the target square-on. BTW one bullet was loaded cup first and the other flat nose first. I was able to recover the bullet from the 210 gr load and it showed good bullet engraving from the rifling. Never could find the bullet from the 240 gr load. No Chrono data, but should be a 1600-1700fps load.
H&R/NEF ignited the .50BMG primers just fine with my rims adjusted for zero headspace with no tinkering needed and the fired cases were ejected over my shoulder. For a $300 gun and 6 hrs of gunsmithing this has got to be the most bang for the buck there is.-Rob

quote:

For a $300 gun and 6 hrs of gunsmithing this has got to be the most bang for the buck there is

Absolutely...!!!! Wouldn't be suprised if you got a call from some paramilitary/park ranger/whaling organization for a hundred of em..!!

Macifej- I have to say that I was really impressed. Gotta give Ed credit for the NEF idea, but this is a totally cool gun and some serious power for very little money. I'll post some pics tomorrow but the effect on the guys at the range was amazing. I could have taken a dozen orders after they witnessed the Big Kahuna load! a picture taken at night would be amazing. I'll bet the fireball is 10 ft around the muzzel. Interestingly, I didnt find much unburned powder.I also think the NEF barrel is on the generous side and a .7295 bullet is closer to optimum than the .7290's I shot.
Gibs - You know that in the high pressure 12GafH I had some one ounce sabots go over 4000fps. I'd imagine some Al bullets would get pretty close to that. I'll have to give it a try in the NEF sometime soon. -Rob

Maybe speeding the powder up to RL22 will give you more velocity and less flash...?? If you could get the time (and license) a run of 20 or so complete from scratch units would be an easy sell...

Talk to you-know-who waaaaay east of you about making a batch of proper brass too...

Cant wait to see the "Satans Single Shot" article in gunrags

Can we get video?

I used Rl22 for top end loads in the high pressure Borchardt gun. Have to run the calulations for the NEF but my first reaction is pressure might get too high too quickly withRL-22. Even Rl-25 might be too much.

Boomstick- Satans Single Shot! Thats hysterical. I love it! -Rob