Bullet Expansion Test: T-C 10" 7mm TCU
Copyright 2011 by Junior Doughty

Article #1 on 14" 7mm TCU

Top = 10" 7mm TCU barrel.  Bottom = 14" 7mm TCU barrel. I deer hunted for several years with the Super 14" 7mm TCU barrel shown in the bottom of this photo. The scope is a 4x Burris. My load was the 154 gr Hornady SP @ ~1750 fps. I never got a shot at a deer.

First, I am not an elevated stand hunter. I hunt on the ground, either in a thicket or at the edge of a thicket. I sit on the ground, on a stump, a log, or on a portable tripod stool. I always situate myself where I have something on which to rest the side of my hands as they hold the pistol in the aiming position. However, deer seldom show themselves in the spot a hunter considers most likely, so a carefully selected rest is often useless.

Mr Buck or Ms Doe suddenly appear at the far left instead of straight ahead, and the hunter has to shoot offhand. That long, heavy 14" barrel held out at arm's length was unwieldy to say the least. And that 4x pistol scope had only an 11 ft Field Of View @ 100 yards. My arms would get tired of holding out the heavy and wobbly pistol while I frantically searched for a deer in the scope, a deer I could see with my bare eyes but couldn't find in the scope if my life depended on it. So I stopped deer hunting with my 14" T-C 7mm TCU pistol.

Then I bought an octagon 10" 357 mag Contender barrel for crawling through a thicket after Ol' Mossy Horns. (See the article here.) It was a much better ground hunting pistol than the 14" barreled pistol. It was lightweight and easy to hold at arm's reach. The fiber optic sights were easy to aim out to what I considered its maximum range of 75 yards.

Then I spotted a used T-C Contender 10" bull barrel in 7mm TCU for sale on a forum. I bought it. I put a new Burris 2x20 pistol scope on it, and I was soon pistol-hunting again.

If the reader wonders why I didn't buy one of the handcannon barrels available, the answer is one word--recoil.

The Contender with its new 10" barrel handled like a dream in the woods. The 2x scope with its 24 ft Field Of View was perfect for maximum 125 yard shots. But all wasn't perfect.

The 154 gr Hornady SP bullets clocked 1750 fps through the 14" barrel. I doubted they would expand much on a deer with lower 10" velocity of 1622 fps. The gun forum experts all said--That ain't nearly enough velocity. Get yourself a 7x30 Waters or a 7-08 barrel!

Not! I decided to do a wet newspaper expansion test on the 154 gr Hornady and all the other jacketed 7mm bullets in my reloading supplies. (I KNOW WET NEWSPAPERS AREN'T THE SAME AS DEER FLESH.)

An expansion comparison test would show me which of my 7mm bullets would expand the best at 10" barrel velocities. Those bullets were:

  • 175 gr Hornady RN
  • 175 gr Nosler Partition
  • 154 gr Hornady SP (tested @ 14" velocity)
  • 140 gr Nosler BT
  • 120 gr Sierra Pro Hunter

Gray Cat & Patch Cat So I put a big trash can out front and asked my newspaper man to please put his old papers in it. A week later, it was full to the brim. Here you see it beside my porch. I simply filled it with a water hose, and when the water drained out of holes in the bottom, I leaned it over against the porch.

There's 28" of newspapers in the trash can as you see it here. When they soaked up water they swelled, and I had to remove the stack you see on the right edge of my porch. They increased in volume by 1/3 or more.

I stood on the edge of the porch and from a muzzle-to-wet newspapers distance of maybe 4 feet, shot down into the wet newspapers.


I experienced no back splatter at all, but a 7mm TCU is not a high-intensity round. I wouldn't try this with a 300 mag!

154 gr Hornady SP & 120 gr Sierra Pro Hunter

On the right, see both the recovered 154 gr Hornady SP and 120 gr Sierra Pro Hunter.

The wet newspapers wore the noses off the bullets, but that's all--zero expansion. Both bullets could be loaded again and shot again.

  • The 154 gr Hornady @ ~1750 fps stopped at 18 1/2".

  • The 120 gr Sierra @ ~1800 fps stopped at 15 1/2".

Obviously, neither of these two bullets are suitable for deer hunting with a 10" 7mm TCU or even with a 14" 7mm TCU.

I actually shot two 154 gr Hornadys through the 14" Contender barrel. (The neck-sized rounds previously shot in the 14" barrel wouldn't chamber in the 10" barrel. I now full-length resize all cases.) Both 154 gr bullets displayed an unusual trait--veering from a straight path through the wet newspapers. One turned almost horizontal and zipped out the side of my trash can at the 16" mark. Luckily for me, it zipped into the woods.


The one which stopped at 18 1/2" and is shown above, veered ~7" off the flight path.

The two bullets above punched caliber-size holes through the wet newspapers. All of the following bullets blew 1" to 1 1/2" diameter cavities almost their entire paths through the wet newspapers.

175 gr Nosler Partition

At ~1600 fps, the 175 gr Nosler showed good expansion in wet newspapers. I recovered the bullet you see here on its side--on its side!--at the 12" mark. It might have gone out the bottom of my trash can if it hadn't been traveling sideways!

The insert shows the base of the bullet malformed into an oval by the sideways travel. That bullet turned sideways at the ~8" mark, but it kept going straight but still sideways until it stopped at the 12" mark. In a deer, it would have created massive tissue damage.

It weighs 154.5 of 175 grs so it lost 20.5 grs of its nose. Going sideways through wet newspapers probably scraped off a good mushroom. This bullet is perfectly adaquate for hunting whitetail deer from a 10" 7mm TCU barrel.

175 gr Hornady RN

This bullet has exposed lead on its tip, so I added a 1/8" x 1/8" hollowpoint to some tips with the hollowpoint attachment for my Forster case trimmer tool. (See photo below.)

Left to right, here we see a new bullet, a recovered bullet which had an added hollowpoint, and an unaltered recovered bullet. Both recovered bullets fired at ~1600 fps muzzle and impact velocity.

Here's the wet newspaper data:

Hollowpointed bullet:

  • Penetration = 9 1/4"
  • Weight = 164.0 of 175 grs
Unaltered bullet:

  • Penetration = 19"
  • Weight = 170.0 of 175 grs
IMHO, a 1/8" hollowpointed 175 gr Hornady RN bullet is perfectly adequate for deer hunting with a 10" 7mm TCU, and the unaltered version is adequate.

Here we see a fist-full of loaded hollowpoint rounds. The hollow in the round on the left is off center, which evidences an operator malfunction with the Forster hollowpoint attachment.

The Forster Hollow Pointer Accessory retails for around $22 and comes in 1/8" and 1/16" sizes. There's full instructions on their web site.

140 gr Nosler BT

Estimated impact velocity = 1755 fps. I say "estimated" because a velocity test with this bullet killed my Chrony.

  • Penetration = jacket = 10 1/2";
    core = disappeared.
In spite of the jacket/core separation this bullet showed the best expansion of all the above bullets at 10" 7mm TCU velocities.

I'll now go out on a limb and declare the 140 gr Nosler BT the most suitable for deer hunting of all the bullets I tested at 10" 7mm TCU velocity.

There's one other thing to look at when considering all the above suitable bullets--their 125 yard velocities @ 10" 7mm TCU muzzle velocities. Here they are:

Remaining Velocities @ 125 Yards

  • 175 gr Nosler Partition w/BC of .519 = 1455 fps
  • 175 gr Hornady RN w/BC of .260 = 1316 fps
  • 140 gr Nosler BT w/BC of .485 = 1589 fps
No limb required--the 140 gr Nosler BT is clearly the best choice for deer hunting with a 10" 7mm TCU @ 125 yards maximum range.   Test over.

Hold on to your hat!   The test ain't over!

Update 3-16-11

The thought struck me to take my Harbor Freight cut-off tool (#42307 $24.99 in March 2011) and whack off the tips of some non-expanding Hornady 154 gr SP bullets. Maybe they would expand in my trashcan full of wet newspapers.

Here in the cut-off tool's little vise, see a freshly modified 154 gr SP bullet—now a FP bullet. On the right, that's a pile of cut-off tips and copper/lead sawdust. Yes, I used safety goggles and a face mask.

WARNING #1: Chips flew everywhere!

WARNING #2: Don't cut the tips off bullets with an exposed lead base! Pressure will sometimes blow the lead core out the bullet nose and leave the jacket in your rifle bore!

As the cut-off blade was only a couple of inches above the bullet, I turned the tool OFF and waited for the blade to stop spinning before I stuck my fingers in there and removed the altered bullet. Otherwise, flesh & BLOOD could have flown everywhere!

I adjusted the cut-off bullet length via a 1/4" bolt with a jam nut. I pushed it in behind the bullet, jam nut against the vise left edge, bolt base against the bullet base, and tightened the jam nut when I thought the cut-off spot looked right. My mind visualized a meplat like on a Lyman 311041 cast bullet. First try, that's exactly what I got—it looked to me like a jacketed 311041, as you can see below.

I ran a weight SD test on a random 10 of 65 bullets sample:

  • AV = 145.56 grs
  • High = 146.6 grs
  • Low = 144.8 grs
  • ES = 1.8 grs
  • SD = .526 grs
That 1.8 grs ES isn't target bullet quality, but it's OK quality for a 125 yard max hunting bullet.

The wet newsprint results were beyond my wildest dreams. Left to right, see an unaltered 154 gr SP bullet, an altered now-FP bullet, and the most effective-looking jacketed bullet mushroom I've ever removed from wet newsprint.

Here's the wet newsprint data:

  • Velocity from a 10" 7mm TCU barrel = 1765 fps
  • Penetration = 12 1/2"
  • Cavity = 1 1/2" from 2" to 6" and 1" on both ends
  • Retained Weight = 142.0 grs of 145.5 grs or an almost unbelievable 97.6 %
  • Mushroom Diameter = ~.615" or ~2.7 X original bullet diameter
At the shot, a literal gray goo geyser erupted from the bullet hole in the wet newspaper stack. As the stack was angled toward me due to the leaned over trashcan, the gray goo covered my pants legs, my shoes, and the edge of the porch. And, no, there was no water in the trashcan. Nothing but wet newspapers exactly like with all the previous shots with other bullets. I never saw anything like the geyser effect of that FP shot. I didn't actually see the geyser due to the recoil of the pistol, but I sure saw what it did—gray goo everywhere.

The shock wave generated by the bullet's flat nose must have atomized the wet newsprint. Then when the bullet caught up with and passed the shock wave and the atomized gray goo, the shock wave and the goo took the path of least resistance and went backwards up the bullet hole and out of the newsprint stack. Maybe so, maybe not. All I know for sure is that a gray goo geyser erupted from the bullet hole and got on me and the edge of my porch. I had always believed in the old "a wide meplat is better" theory, but after that shot I'm a confirmed believer. No wonder a 30-30 Winchester works so well on deer.

Here's a close up of an altered nose. This meplat measured ~.175" diameter or ~ 62% of bullet diameter. It compares favorably to a 311041 meplat at ~68% of its bullet diameter.

I randomly selected 3 altered bullets and loaded them for an accuracy test on my front yard range.

  • Range = 50 yards
  • 3 shots = 5/8"
In my opinion that was outstanding accuracy with home-altered bullets and a 2x scope. Plus, the POI was an easy-to-adjust 1" left and 1" low from the 175 gr Hornady RN hollowpoint POI.

With an estimated BC of .270 and a measured 10" 7mm TCU muzzle velocity of 1765 fps, the altered bullet's remaing velocity @ 125 yards = 1483 fps.

I now have a thicket-hunting dream of a pistol, I believe. You fellows who deer hunt with a 7mm TCU, a 7mm BR or a 7-30 Waters might consider investing ~$25 with Harbor Freight and ~$25 with Hornady. Then you can make yourselves possibly the best deer bullet for those calibers—a homemade Hornady 145.5 gr FP. If you're a traditional kind of fellow, call it a jacketed Junior041.

Update 5-09-11

This bullet came from a group buy mould on the castboolits forum back in 2006. They called it the "7mm soupcan." It's available today (May 9, 2011) in the SPECIAL ORDER MOULDS section of MidSouth Shooters Supply in both 2-hole and 6-hole versions (about $18 and $36).

This bullet's naked OAL = .865". The meplat's diameter = .170" or ~ 60% of bullet diameter. I estimate the BC at .230. Bullet alloy = ACWW. Lube = LLA two coats. Sized .285" with a Lee push-through die. RTL weight = ~ 137 grs and naked weight = ~ 133.4 grs.

It shoots fine in my 10" T-C 7mm TCU, i.e., 3 shots in ~ 5/8" @ 40 yards. At 1657 fps with 2¢ of surplus WC820 (n), the mangled bullet above stopped at the 14" mark in my stack of wet newsprint. The chunk of lead and the old Lyman non-crimp gascheck both stopped at the 8" mark.

It blew a 1" to 1 1/2" cavity from newspaper surface to the 11" mark with a bullet diameter cavity from the 11" to the 14" marks. This bullet produced arguably the best wound cavity of all the bullets I tested + it gave outstanding penetration in spite of its low impact velocity of ~1657 fps. However, it produced no gray goo geyser, dang it....

The recovered bullet weighed exactly 103.3 grs minus its lube, the chunk of lead and the mangled gascheck. Its retained weight = ~77% of its naked weight.

With its good mushroom and surprisingly deep penetration, I see no reason not to use this bullet @ 1657 fps for side-on shots at deer to 75 yards max. Plus, there's a coyote named "Soupcan" running around my river bottom.