Forming 7mm TCU

[HighlandLofts]

I will be forming 223 brass in to 7mm TCU.

Any advice?

Also can 5.56 brass used to make 7mm TCU?

DO any of you add a filler after the powder charge to take up the slack space in the cartridge for better accuracy?


I have a T/C 14 inch Contender barrel, an extra frame with pistol grip, a set of dies and several powders I can use.

All I need is bullets and a synthetic forend to make this a working handgun.

Any one have an extra forend that you want to sell?

 

[gun_slinger_boy]

That looks like a pretty straight forward conversion. Probably don't even have to use wax. When you press it just do it in a moderate speed and controlled pull. I would imagine you could use 556 brass as long as the psi for 556 is inline with that of the 7mm. Either that or you would have to use lighter loads for the 7mm. Brass forming is a fun and useful skill to have.

 

[HighlandLofts]

It would seem the 5.56 brass would be stronger tjem the regular 223.
I'm not sure what the difference is between the two. I have a whole bunch of both to use if both will work.
I have a Contender in 35 remington that is fun to shoot.
The 7mm TCU is suppse to be accurate and low recoil.

 

[Acer-m14]

oh brain fart .. I think its on a 300 blackout forum .. a list of a bunch of 223 cases with wall thickness's
brb switching to phone ...

Back

STICKY - Good/Bad brass list converting 5.56->300blk - 300BlkTalk

maybe that can help with your choices ..

 

[gun_slinger_boy]

Dimensionally 223 and 556 are identical on the outside. 556 tends to have thicker case walls however than 223. 556 also tends to be loaded hotter than 223. Even though 556 is loaded hotter it will usually create less chamber pressure in a 556 chamber than a 223 in a 223 chamber. This is because the 556 tolerances are more loose than those of 223. Conversely the 223 tends to be loaded lighter than 556 but produces higher chamber pressure due to the chamber specs that come closer to the exact dimensions of the casing. But as long as you keep the 7mm loads in line with the pressures the 556/223 are able to withstand you should have no problem using either. As Acer has mentioned an issue that can arise is if the case walls are TOO thick making the bullet hard to seat and or make the round too tight to fit in the chamber. I personally use 556 brass from lake city to form my 300 blackout rounds.

 

[Acer-m14]

This is because the 556 tolerances are more loose than those of 223.

Imho .. from my reading it all in the 556 chamber .. the jump to the lands .. the diff from 223rem and 5.56 nato .. its been a bit .. but the land jump is
bigger in the 5.56 nato because of the bullet they used .. not always 55gr .. i think some were in the 60's ..

pop a 5.56 nato in my mini 14 223rem and that nato round might be into the lands .. then i get the high chamber pressure .. ..

As Acer has mentioned an issue that can arise is if the case walls are TOO thick making the bullet hard to seat and or make the round too tight to fit in the chamber.

it will fit with no prob .. the thicker wall is less volume for powder .. ie compressed loads ..

 

[gun_slinger_boy]

Imho .. from my reading it all in the 556 chamber .. the jump to the lands .. the diff from 223rem and 5.56 nato .. its been a bit .. but the land jump is
bigger in the 5.56 nato because of the bullet they used .. not always 55gr .. i think some were in the 60's ..

pop a 5.56 nato in my mini 14 223rem and that nato round might be into the lands .. then i get the high chamber pressure .. ..

Yup. The 556 chamber isn't as close to spec as the 223. 556 isn't SAAMI spec by the way, 223 is but you'll rarely ever find a SAAMI spec 223 barrel. I would think the looser tolerances in the 556 chamber would be for reliability's sake (fouling). Especially in machine guns.

 

[Acer-m14]

@gun_slinger_boy i have heard some mini 14's in 223rem are ok for 556 nato .. i might have to call Ruger

 

[HighlandLofts]

I have been picking up brass at the gravel pit where I go shooting and sent a ton of it to my oldest son, when I started reloading I have been saving most of it. I have been depriming it and tumbling it for future use.
Yesterday and today I cleaned up some 223 and 5.56 to use. This is about half of what I have.



I think I will separate some of the brass by headstamp to use in the remington 700 with the bull barrel and then I will form some in to 7mm TCU to try out in the contender.
I will try with iron sights at first then mount a scope I have on it and try it again.

From what I have read the 7mm TCU will get inch groups at a hundred yards.

I want to get the forend and projectiles to load up some ammo for next weekend.

 

[HighlandLofts]

A pic of the 7mm TCU



The 7mm TCU on the left and the 35 Remington T/C Contender on the right.




I have a 22lr contender as well and a couple of other barrels tucked away some where in the gun room..

The 7mm TCU IS WHAT I want to work out on.


After this is over with I bought. A Remington XP100 in 7mm BR a couple of years ago I haven't shot yet. My son shot one bullet threw it when he came out here a year and a half ago.
I did find two boxes of 7mm BR ammo for it at a gun show and I bought a set of dies.

This will.all be fun and rewarding when I get them in tune and my grandson gets to shoot them.

 

[HighlandLofts]

I am going to form up a hundred cases, tomorrow I will pick up some 7mm bullets and load them.

 

[gun_slinger_boy]

Easy right?

 

[HighlandLofts]

Real easy, I used a very small amount of ButterBore for black powder lube on a Q-tip to lube the inside of the necks and sprayed the outside with Hornady One Shot Lube. I had a little over 150 cases resized, so I primed them. I am going to resize enough to use up the rest of the primers in the hand primer.

Out of the 150 or so cases I resized, six split.


I crush the bad cases before I toss them in the recycle brass bucket. Two I already crushed.



Tomorrow on the way home from work I am going to stop by a gun shop to pick up a couple 100 count 7mm projectiles to load up the brass I have prepped for next weekend.

If I don't get a forend to complete the gun by then I will rob the one off of the other Contender to use.

I have several types of powder to use, once I get these cases fire formed I might buy some different powder to try.

I will load some down at the starting point to see if my grandson can handle the recoil.

 

[Acer-m14]

@HighlandLofts

https://www.amazon.com/Now-Foods-So...qid=1531715549&sr=8-2&keywords=liquid+lanolin

https://www.amazon.com/ISO-HEET-282...1531715658&sr=8-1&keywords=heet+gas+treatment

or 99% rubbing alch.

works just as good as one shot from my experience so far ..

 

[HighlandLofts]

I watched the video, I'll have to pick the stuff up and give it a try. I still have a small and a big spray can of one shot.
I like to spray the straight walled handgun cases before resizing even in carbide dies, the spray is so much easier then they other type of lube.
Thank you for the links.

 

[Acer-m14]

@HighlandLofts no prob .. just keep it warm .. the lanolin with turn to a solid in the cold .. .. just shake up the bottle to keep it mixed ..

 

[HighlandLofts]

I looked at the Wal-Mart website and I can order the stuff threw them with free shipping or store pickup.

I'll pick up a good spray bottle, we might have a close to empty one under the sink for window spray or something, I want a see through bottle so I can see what' happening with the mixture.

Reforming the brass it was all one head stamp that I had a problem with, split cases, primers not sinking deep enough or not aliening.
Tonight I will go through primed cases and see what the ratio is between that one head stamp and all of the others.

As far as the split cases I think if i annealed the brass I wouldn't of had that many, it was probably 5.56 brass, I don't know what the head stamp on the screwed up cases stand for, I'll find out

 

[gun_slinger_boy]

The lanolin shouldn't separate if you have the correct alcohol to lanolin ratio. I used the same kind as in the above video that was ordered from ebay. I bought four of them but am still on the first bottle that I mixed years ago lol. I'll see if I can take pictures tonight but the mixture should stay a nice transparent color without having to be mixed. If you get separation you need to add just a bit more alcohol until there is no more separation.

ETA: I used iso heet for the alcohol. I think it's much better than rubbing alcohol

Advance Auto Parts - Down for Maintenance

 

[HighlandLofts]

I need to order the lanolin, I still have two cams of Hornady One Shot left.

I picked up a 100 pack of Speer 145 grain jacketed soft points to use for my fire form projectiles. They were the cheapest they had in stock, $27.99 & tax.
The Hornady book doesn't have a load for that weight for the 7mmTCU,
The Lee Book has loading data for 145 grain lead cast bullets.
They have loading data for 140 grain and 150 grain jacketed bullets, so I think I might split the difference and go with that.

These are the bullets I bought.


Here is the contender put together.