Sub .30 Straightwalled Cartridge for High BC Subsonic in Longbarrel Rifle

[SmallBoreBuyer]

Hello All,

Longtime lurker, first-time poster.

I am interested in a single shot rifle built around a rimmed, straight-walled (possible to change this parameter), sub .30 that can launch a long, high ballistic coefficient boolit at subsonic velocities. I am considering the .22 straight walled centerfires, .25-21, 270 Ren, and am open to others that I have not considered. This is the first build like this I have considered and am open to suggestions, insights, guidance, etc.

Thanks so much,

John

[rking22]

Welcome, I see you are considering the 270Ren. That would be my suggestion, I have saved a picture of it with a cast boolit and plan a project with it when I get a roundtuit :) Watching with interest !

[Nobade]

I have a .27 Hornet, same thing as the Ren except you use the Hornet case at full length. Works great, loads with Ren dies, and I recommend it highly. .25 Hornet with an appropriate throat and rifling twist would be interesting as well, but can't handle 150gr. bullets like the .27 can.

-Nobade

[jhalcott]

Is this going to be used for targets or poaching ? I think a larger caliber might be better. A 357 diameter bullet would be good for 50 yard targets at low velocity.

[Artful]

Sort of like inventing a 300 whisper all over again, except you want straight walled.
http://www.thefirearmblog.com/blog/wp-content/uploads/2012/05/300_vs_32_20-tfb.jpg
If I wanted something rimmed I'd look at 360 DW brass should make for a perfect "rimmed"
300 Blackout or necked to 7mm or 6.5mm.

Oh, and a listing of previous <.30 straight rimmed cartridges for you.
5mm Brun
5.5mm Velo Dog/5.75 Velodog
230 Revolver
6mm Beaumont Pistol
6.35 x 22 Roth
6.6mm Mauser rev
270 REN (blown out 22 Hornet)
7mm Galand
7mm Sarbacanne
7mm French Revolver
7.5mm Swedish & Norwegian Nagant
7.5mm Swiss Army
7.6mm Mannlicher
300 Revolver

[SmallBoreBuyer]

Is this going to be used for targets or poaching ? I think a larger caliber might be better. A 357 diameter bullet would be good for 50 yard targets at low velocity.

Informal target and plinking - but, like all of us, I like an accurate rifle.

[2ndAmendmentNut]

If you want to take the simple route I would suggest you get yourself a TC Encore frame and take a look at MGM's custom barrel and caliber selection. I personally had the same idea of having a subsonic straight walled case only in 38cal. I was going to have MGM make me a 357max barrel with a fast twist for stabilizing long boolits at low speed, but all I need is time and money. Perhaps one day I'll get back to my subsonic 357max idea.

[SmallBoreBuyer]

I have a .27 Hornet, same thing as the Ren except you use the Hornet case at full length. Works great, loads with Ren dies, and I recommend it highly. .25 Hornet with an appropriate throat and rifling twist would be interesting as well, but can't handle 150gr. bullets like the .27 can.

-Nobade

This is very interesting.
Do you have a source for brass?
Is anyone chambering rifles in this cartridge?

[SmallBoreBuyer]

Sort of like inventing a 300 whisper all over again, except you want straight walled.
http://www.thefirearmblog.com/blog/wp-content/uploads/2012/05/300_vs_32_20-tfb.jpg
If I wanted something rimmed I'd look at 360 DW brass should make for a perfect "rimmed"
300 Blackout or necked to 7mm or 6.5mm.

Oh, and a listing of previous <.30 straight rimmed cartridges for you.
5mm Brun
5.5mm Velo Dog/5.75 Velodog
230 Revolver
6mm Beaumont Pistol
6.35 x 22 Roth
6.6mm Mauser rev
270 REN (blown out 22 Hornet)
7mm Galand
7mm Sarbacanne
7mm French Revolver
7.5mm Swedish & Norwegian Nagant
7.5mm Swiss Army
7.6mm Mannlicher
300 Revolver

The whisper is a good analogy, but I am seeking a cartridge of a smaller caliber. The straight-walled criterion is mostly a result of my research into cartridge capacities versus velocity. Straight walled cartridges can push a bullet well over the speed of sound, so going to a shouldered design seems to be more complex in reloading and a waste of brass.

[SmallBoreBuyer]

If you want to take the simple route I would suggest you get yourself a TC Encore frame and take a look at MGM's custom barrel and caliber selection. I personally had the same idea of having a subsonic straight walled case only in 38cal. I was going to have MGM make me a 357max barrel with a fast twist for stabilizing long boolits at low speed, but all I need is time and money. Perhaps one day I'll get back to my subsonic 357max idea.
I have thought a lot about this, but would prefer a smaller caliber answer to save on lead and powder.

[2ndAmendmentNut]

I have thought a lot about this, but would prefer a smaller caliber answer to save on lead and powder.

I understand. Still might suggest getting in touch with the nice people over at MGM. I would think a 32 H&R or perhaps even a 327federal could be straight tapered down to a 30cal. End result would probably look like a scaled up 22hornet.

[Nobade]

This is very interesting.
Do you have a source for brass?
Is anyone chambering rifles in this cartridge?


Hi,
For brass you just use normal 22 hornet cases from any of the manufacturers. Either fireform them with crem 'o' wheat or use the Ren dies with their tapered expander plug to open up the mouth.

As for building rifles, I suppose any gunsmith could build one. I did mine on one of those old Sako hornet actions, just a barrel replacement. I didn't have a chamber reamer as such, but since there is no taper to the case I just used an appropriate decimal sized chucking reamer to cut the body and a .270 throater to cut the throat. Mountain Molds made my bullet mould, a 95gr. LBT style beauty that is the perfect size for a case of this capacity. It's plain base, and I run it at 1700 fps with Lil' Gun and filler. If I paper patch it I can hit 2200 fps with a case full of Lil' Gun. There's no reason the same rifle couldn't fire a 150gr. bore riding cast bullet at 950 fps also as the OP wished to do.

-Nobade

[Nobade]

I understand. Still might suggest getting in touch with the nice people over at MGM. I would think a 32 H&R or perhaps even a 327federal could be straight tapered down to a 30cal. End result would probably look like a scaled up 22hornet.

The regular TC 32 H&R mag Contender barrel is .300" X .308", 1:10 twist. It has a tapered throat to allow firing either normal 32 H&R bullets or 30 caliber rifle bullets. It will stabilize a 220gr. Krag cast bullet at subsonic speeds. I had forgotten about that one, used to use it in big bore pistol silhouette matches. Very quiet and hits hard. If you were to build a rifle like that it would probably be a lot of fun.

-Nobade

[leadman]

There is the above mentioned 300 Whisper with the chamber cut for a rim. With a T/C it only takes the change of extractor to go from rimless to rimmed. One of the big name shooters uses the rimmed version but can't recall his name.
There is also a 38 Special case necked to 30 caliber, the 30 Reece. Go to Specialty Pistols for info on it.
Costs will quickly escalate building a rifle for cases that do not already have reamers produced for them or dies. Don't know if this is a concern or not. The use of abundant and easily purchased cases keeps costs low.
I have shot a 10" T/C barrel with a 10 twist and my 18" 8 twist both in 300 Whisper. I prefer the 8 twist for heavy bullets or boolits as it seems to more accurate and stabilizes 240gr bullets.

[357Mag]

Smallbore -

Howdy !

.22-15-60 Stevens

Re-production brass is available. Small primer


With a simple shoulder:

.22 " Jet "

.256 Win

.357Max necked -down to .224" cal, using a slightly shortened .222Rem die. Results = an Americanized 5.6 X 50R.


With regards,
357Mag

[rking22]

300AAC reamer and 38 special brass. Cut the rim with a single point tool, use the AAC dies shortened to form and load. You can throat it for what you want, or extend the neck to use 357 brass. That is if you just want a powder/lead efficient round. It's not straight walled or sub .30. Now if sub .30 is really important, there are 7TCU 6x45, ect all could be used chambered short with 38 brass. For that matter the plain ole Hornet is real close to perfect, talk about conserving lead and powder! I still Like Nobades long REN,,, just looks,for all the world, like a mini 3855!

[nseries]

.30 Carbine? Except it's rimless. Brass, dies and reamers readily available.

[BAGTIC]

I too have a .27 Hornet. It should be able to produce high subsonic or transonic velocities in any rifle barrel with bullets to 150 grain.

Don't worry about high B.C. bullets. At subsonic velocities round nose bullets often (usually?) have less drag than spritzers. This is part of the success of the old RN black powder loads firing high S.D. bullets at transonic velocities. It is also the reason .22 RF bullets are basically RN.

[JHeath]

You are wasting a rifle if you chamber it for anything but .277 Bird Poop:

http://castboolits.gunloads.com/showthread.php?246638-Looking-for-opinions-(brace-for-impact)-270-REN-in-an-1885-Low-Wall

[JeffinNZ]

I have a Martini .32-20 with an 18 inch SMLE barrel. I can happily stabilise and accurately shoot cast bullets up to 240gr easy.

[Chev. William]

Have You considered .250" or .251" diameter Bullets in a straight Walled Reformed .22 hornet or 5.7x28mm parent Case?
The Reformed Hornet with a body diameter of .276" has an Untrimmed Length of about 1.380" and can be Made with effort In one Stage of sizing but would be less effort if two Stages are used.
The 5.7x28 can be Reformed in three stages of resizing to .276" body diameters and lengthens to nearly 32mm in the Process, Yielding "6.35x32mmSR" cases.

Ammoguide International has two "Mildcats" Listed in 6.25mm Sizes: the "6.35x32mmSR" and the "6.35x28.6mmSR" which could, in a STRONG action, be loaded to the CIP Maximum Average Pressure of 50,000psi.
There is also the Hornet derived ".25-10 Halsted" sued to replace a .25 Stevens (Long) RF cartridge but it would have the 40,000psi MAP limit of the Hornet in a STRONG action.
Resized .257 Bullets (down to .250"-.251" ) are a Possible source of Heavy for Bore Bullets.

The Present commercial Barrel available is the Lothar Walther ".25ACP/6.35 Browning" pistol Barrel Blank with a Twist of 9.8" to 1 Turn that is 23.8" long and 1.1" in diameter.

Best Regards,
Chev. William

[marlinman93]

I own a Stevens Walnut Hill in .25-21 Stevens, and it's a great cartridge. The one big drawback is the brass. Not a donor cartridge around to use to make brass, so brass is expensive. Bertram makes new, and it's junk. Lost half my Bertram brass on the first firing. Loads that were used with 100+ year old brass had been reloaded with for decades, and never split!
I went to Rocky Mountain Cartridge lathe turned brass, and no more problems. But man is it spendy! If I wanted a sub .30", subsonic, straight walled case, I'd probably fudge and get a bottleneck case that's cheaper instead. Lots of great choices, and cheaper too! Not sure why your case needs to be straight wall?

[Chev. William]

Check out:
6.35x28.6mmSR Stewart, a Viable Modern Cartridge (http://castboolits.gunloads.com/showthread.php?293045-6-35x28-6mmSR-Stewart-a-Viable-Modern-Cartridge-conversion-for-25-Stevens-Firearms&highlight=.25+Stevens)
.250/.257 Cartridges to .25ACP/.25 Stevens (http://castboolits.gunloads.com/showthread.php?283914-250-257-Cartridges-to-25ACP-25-Stevens-Diameters-from-5-7x28mm-once-fired-brass&highlight=.25+Stevens)
The 6.35x32mmSR STEWART "Mildcat", a potential (http://castboolits.gunloads.com/showthread.php?286203-The-6-35x32mmSR-STEWART-quot-Mildcat-quot-a-potential-Cheap-Cartridge-to-shoot&highlight=.25+Stevens)
reloadable .32 rimfire brass (http://castboolits.gunloads.com/showthread.php?147224-reloadable-32-rimfire-brass&highlight=.25+Stevens)
All of Them Have information that may be useful to you in Your Quest.

Best Regards,
Chev. William

[wlc]

If you want to take the simple route I would suggest you get yourself a TC Encore frame and take a look at MGM's custom barrel and caliber selection. I personally had the same idea of having a subsonic straight walled case only in 38cal. I was going to have MGM make me a 357max barrel with a fast twist for stabilizing long boolits at low speed, but all I need is time and money. Perhaps one day I'll get back to my subsonic 357max idea.

I have that combo. Had MGM make me a, IIRC, 12 twist 16.5" barrel in 357 Max. I really like it. Had Tom at Accurate cut a 4 cavity mold with 2 dropping a 250gr and 2 dropping a 300gr both plain based. Lil gun has worked best with the 300gr so far. I still need to do some playing around with loads for the 250gr. I'll get back to it when I get tired of playing with the 300blk barrel and subs. Nice and quiet combo when shot through my Liberty Mystic. Also packs a lot of thump.