7mm TCU vs 300 Whisper

[wellfedirishman]

Folks, I am looking for your thoughts on these calibers.

I have a 7mm TCU which I picked up recently. I put together some light loads (Trailboss) with a RCBS 145 grain cast bullet and it provided a reasonable starting point for accuracy at 100 yards:
http://castboolits.gunloads.com/showthread.php?t=113588

I plan to keep the 7mm TCU as a cast bullet shooter primarily.

I have a good stash of 30 cal jacketed bullets (150 grain SPs and 123 grain FMJs) and powder for them.

I was thinking of getting a 300 Whisper barrel (300-221) for use with these jacketed bullets at fast speeds, and also for heavy cast bullets (200 + grains) as subsonic speeds.

This is for paper punching and ringing gongs out to 200-300 meters. I may also use this caliber in an AR later.

So, here's the question:
Is this caliber too close to the 7mm TCU?
Is it sufficiently different to make it interesting of its own right?

Everything I have read about the 300 Whisper is that it is very accurate, both with heavy slow bullets and fast light ones.

Lee makes a 200 grain 30 cal mold that would probably work well at subsonic speeds in this gun, and is cheap at $20. There don't appear to be many options for heavier 30 caliber bullet molds (220+ grains). The Lee 8mm Maximum (225 grains) might work if sized to 309 cal, although it would be a squeeze to size it down.

Does anyone here shoot both of these calibers? If so can you offer an opinion please? What molds do you use?

Edit: These are for use in a TC Contender, with 10"-14" barrel length.

[Artful]

What twist rate is your 7TCU barrel - if you trying for subsonic heavy cast bullets that will be the determining factor. if it's the 1 in 9 twist you should be able to use heavy bullets no problem ( here's a link for it http://forum1.aimoo.com/ihmsa/Bigbore/Heavy-bullets-in-7mm-TCU-1-48997.html ) I remember some of the earlier T/C barrels having severe misalignment of the chamber to the bore.

I shoot a 300/221 Fireball (whisper clone) in an AR and it is accurate but heavy bullets subsonic loads suffer from a real drop problem after 150 yards. and make sure you get a faster than 1:10 twist (1:8 or 1:7 for 220+) - if your looking for a mold check out group buy section for 247 grain NOE group buy going on right now.
http://castboolits.gunloads.com/showthread.php?t=102895
http://i69.photobucket.com/albums/i80/swedenelson/1111-134-311247GrFNWhisperCart.jpg
http://i69.photobucket.com/albums/i80/swedenelson/1111-134-311247GrFNWhisper.jpg

300 whisper is more dual use design the 7TCU was more high vel for IHMSA use.

[stubshaft]

I have both of these cartridges. I shoot the 7TCU out of both a 10" and 14" Tender and the Whisper out of a 15" Encore. For all around use and ease of loading I would take the 7TCU hands down. The 9" twist in the factory barrel is great to shoot cast with and the majority of loads that I shot out of it used the same 145gr RCBS boolit. The Whisper is a great cast boolit shooter also. I used to shoot the SAECO 311 out of it and toyed with the heavies also. Like Artful said you will need a 1 in 7 or 8 twist to stabilize the heavier boolit. The key with the Whisper is that you have to decide which boolit weight range you want to shoot out of it and throat it accordingly. If you cut a long throat for 200gr - 220gr boolits, then accuracy will not be as good with the 125 - 150 gr boolits due to the longer jump to engage the rifling. You can have your cake and eat it too if you design a custom mould with a long tapered nose to allow the boolit to fit the chamber. I did this and had Dan make me a 215gr boolit with a tapered nose, which allowed me to seat the GC to the base of the neck and just kiss the rifling.

Both of the calibers are very efficient in their use of powder, but the Whisper will not outrun the TCU. It will get you more velocity per grain of powder but only up to a point. Another caliber you can try is the 30 Herret. It is very efficient, accurate and with a fast twist you can also shoot the heavies out of it.

[stubshaft]

The photo is of the Whisper with groups at 100 yds.

[Ramslammer]

G'Day
I've got both on rifles. The 7mmtcu is used for a 500m silhouette gun and shoots cast at chickens, pigsand turkeys. Change over to jacketed for Rams. Shot a 5" group on a ram @ 500 with a RCBS 168 but it wouldn't go over. 7mm soupcans produced a 2"group @ 200 so I use those almost exclusively. My whisper will shoot RCBS 168, lee 150's and a old 120gc 30m1 mold I have well. If I was choosing one it would be the TCU.
Juddy

[41wyom]

Don't overlook a 30/223. I have an RPM XL single shot with a 1:10 twist and that chambering does well with 185-gr cast bullets. Not much of a shoulder after being reformed but it works. Some other names for it...30 Juras. 30 Silhouette, 30 Apache, 30 TCU, etc..been around since mid 70's. has been used in single shot handguns and rifles. Takes over 500-meter rams in NRA Highpower Rifle silhouette.

[Doc Highwall]

stubshaft, how would you rate the 7mmBr vs 7mmTCU.

[DragoonDrake]

I looked at the 30tcu when deciding pistols for IHMSA. My one worry was not leaving enough brass on the neck. My choice was the 7tcu.

[wellfedirishman]

Thanks guys, I appreciate the information. I think the 300 Whisper is a go then. That group buy mold looks really interesting.

[Doc Highwall]

The 7mm International looks good also, just lube a 30-30 Win case and size and out comes a 7mm International. It is kind of like a 7-30 Waters with the shoulder pushed back for a long neck and less case capacity.

[bearcove]

7mm br is in a different class. It was put in the bolt pistols. Higher pressure and bolt thrust.

[stubshaft]

stubshaft, how would you rate the 7mmBr vs 7mmTCU.

Almost the same capacity but the BR runs at higher pressures. I used one for a little while in Unlimited but found it anemic and sent it to Ralph Bond to rechamber for a wildcat that I designed. The BR is a very efficient cartridge in its own right and is one of the great legacies of Elgin Gates who designed it. It was/is a low recoil accurate round with enough energy to take down rams. But he also went on and designed the IHMSA line too. The TCU in a bolt gun is every bit as accurate as the BR (although for the most accuracy out of a TCU case I like the 6mm). I like the BR but, love the TCU. It is one of the easiest rounds to load for and form. Brass is plentiful and in most cases free (if you hang around the right ranges). Low recoil and probably more accurate then most people are capable of.

[stubshaft]

The 7mm International looks good also, just lube a 30-30 Win case and size and out comes a 7mm International. It is kind of like a 7-30 Waters with the shoulder pushed back for a long neck and less case capacity.

You mean the 7mmINTL-R which is the rimmed version. IHMSA called their 7mm the international also. It is a little overbore for the 7mm as is the 7-30 Waters. It was my first unlimited cartridge and I got my first 40 with it in '84. Loaded the 145 RCBS cast of lino ahead of H335 and used to drill the old soft steel turkeys. I had to cut the "inside" loads by 10grs. or they would be severely damaged also. The only other rimmed cartridge that strikes my fancy is the 7mmUS by EABCO. It is a 219 DW opened up to 7mm. Should provide optimum capacity for a break pistol/rifle.

[bearcove]

I like the 7-30 waters but, have a 20" barrel for it also.

Cheap brass if you use 30-30.

[7br]

stubshaft, how would you rate the 7mmBr vs 7mmTCU.

The contender is generally not chambered for the 7mmBr. Not enough steel left in the chamber to handle the pressure. The encore is a different story.

[stubshaft]

I knew that but did not see the edit stating it was for a Tender. Sorry, thanks for clarifying that 7br.

[Doc Highwall]

I have both Contender and Encore frames. For the Encore for pistol barrels I have 6mmBr., 6.5mmBr., and 7mmBr. and thinking of getting a XP100 in one of these calibers but not sure which one yet. For my Contender I have a Super 14 in 22Lr and a 10" 375 Winchester.

[Idaho Sharpshooter]

The BR cases are basically a 1.520" 308 case. The CBA boys are getting over 2200fps with 200gr .308" boolits. I would hardly call that anemic.

Rich

[stubshaft]

The BR cases are basically a 1.520" 308 case. The CBA boys are getting over 2200fps with 200gr .308" boolits. I would hardly call that anemic.

Rich

I doubt that they are getting that out of a 15" barrel, and if they are more power to them. I was hard pressed to get 2400fps out of a 7 IHMSA with a 175gr boolit and the pweders available at the time. I have a great respect for the CBA guys and their abilities to get small groups. But it is a far different game from knocking down a forty eight pound ram at 200 yds. The 7BR has the ability to do so but not as efficiently as some other calibers, and it was in this light that I called it anemic.