WTB/WTTF: 7mm TCU chamber reamer

[BK7saum]

I will be taking lathe and rebarrelling classes this summer and would like to build a 7mm TCU on a remington 700 short action receiver. I have zero lathe experience at this point.

I had a switch barrel 223 and 300BLK that never got switched from 300BLK, so I purchased a BDL action and measured the recoil lug needed. I ordered a recoil lug ground to fit and put together that rifle. Headspace is spot on at Go + 0.001-0.002" The 223 has a 223 follower on a 308 spring and feeds the 80 grain amax bullets seated long just fine (throated for the long bullets). It also feeds standard length 223 bullets well also.

So, I'd like to build the 7TCU along the same line so that I can seat bullets long as needed. The Nosler ABLR bullets out to be the cats meow in the TCU. Although I'll probably run the 120 vmax or NBTs quite a bit too.

So, if anyone has a 7TCU reamer they dont need anymore, I'd like to know the specs, especially freebore, and possibly take it off your hands by trade or purchase. Also, if you have the go gage, I'd be looking for that also.

Thanks for looking.

Brad

[BK7saum]

Back up.

[Red Elk]

PM sent

[BK7saum]

Still looking.

[P Flados]

I just bought and used a previously owned Clymer 7 TCU reamer.

I took a never used 28" 1 in 9" barrel blank I got in from Numerich in a mixed bag barrel purchase and turned it into an AR-15 barrel. I have made a custom NLG bullet mold with a short nosed 133 gr (0.17 meplat) and a short nosed 149 gr (smallish meplat). The short noses will allow loading the 7 TCU to 2.255" for feeding from a magpul mag (side ribs reduced). First trip to the range was very bad, & I ended cutting 1" off the chamber end, cutting new barrel extension threads (I was not happy with the first try) and re-cutting the chamber. Second trip out was much better but not as good as I want. It feeds great, but I am using it "straight pull" for now. Gas block is to be added after I am happy with accuracy. I will continue to work on this new project and see if I can get my new "fun gun" shooting better.

The reamer looked pretty close to new when I got it, it still looks about the same.

The 7 TCU is noted for having long throats. My Contender is over 1/2". The Clymer is right at 0.3".

I had planned on keeping it, but could possibly part with it. Before I let it go, I would probably want to put a chamber in the ~10" cut off left over from the first barrel "just in case" I want to build a pistol length AR.

If no one offers up one for less than say $90 plus shipping, send me a PM.

[BK7saum]

Thanks, I'll definitely keep you in mind. I'm not in a huge hurry. I have a few more weeks to finalize. I just hope the NRA classes aren't cancelled for the summer.

[BK7saum]

Back to the top.

[P Flados]

I have done the second barrel I wanted to do.

It cost me right at $90 with shipping, so I will ask the same.

I took some cases that were fire formed to my TC Contender factory chamber to use as go / no-go gages. I will include them.

One has a number of layers of masking tape on the base such that the base extends out of the chamber ~0.008". I would not want a chamber that would easily close on this length.

The middle one has layers of tape for about flush plus ~0.004". This is probably about right.

The third has no tape and the fired case was confirmed to sit flush. This should be an easy close.

With a bolt gun, be careful to not force the bolt closed using these as gauges. With the small shoulder, you could push it back with too much force.

For a 7 TCU, headspacing is not the same as it would be for a common round. You are not going to worry about bad fit for factory ammo.

So you can compensate for a headspace that is a little "too long" by not running cases 100% into your sizing die after fire forming. This works as long as your converted 223 cases are not "too loose" to even fire.

If you are a little "too short" on headspace, you may not be able to push the shoulder back on a "too long" case when resizing. However, I doubt you will ever get a case fired from you gun that is "too long" to go back in.

Also note that is is a lot easier to "fix" a short chamber than it is to "fix" a chamber that is too long.

[BK7saum]

Back to top. Anyone have a 7mm TCU reamer that they dont need anymore?

P Flados,
PM sent with questions about your reamer.

Brad