Home Forums Hunting & Shooting General Big Game Lets discuss the 7mm STW and 175 Partitions

A few years back I had a 7mm stw built with a M70 action and Hart barrel, great cartridge, mine shot incredible groups. I wanted the best long range performance out of it also and had heard all the theories about how heavier bullets with superior ballistic coefficients shot flatter than light fast bullets. It didn't quite make sense to me so one evening after a few too many beers I sat down at my computer with a ballistics program and started plugging in numbers. The conclusion I came to after playing with the numbers for a while was that there is a point where the superior BC of a heavy bullet will let it retain enough velocity to shoot flatter than the lighter fast bullet. That point was, in almost every scenario, between 700 and 800 yds. In other words, inside 750 yds or so your 175 gr 7mm bullet is going to drop more than a 140 gr bullet shot at an appropriate velocity for the cartridge (300 or so fps faster than a 175 gr for a 7mm stw). If you plan on shooting farther than 750 yds then then heavier bullets will give you a flatter trajectory, inside 750 yds the lighter bullets will shoot flatter. Since I don't plan on ever shooting at a game animal over 750 yds I choose to use the lighter bullets and take advantage of the flatter trajectory they give. I can't envision any scenario where I'd want to use a 175 gr 7mm bullet. If I need that much bullet weight because of the size of the game then I have a 300 mag, 338 mag, and 375 H&H. I personally see no reason to use anything other than a 140 gr bullet of good construction out of a 7mm stw. Using anything heavier slows it down and takes away the flat trajectory.

I wondered how long it was going to take before someone brought that up.....

Crowhunter:What you say about the trajectory issue is true enough IME shooting out to 600 yards.Neverthless, a 160 from an STW at 3250+, or a 175 at 3100, is no slouch in open country. And for those disinclined to own a bunch of calibers,and use the big 7 for everything,either the 160 or 175 are handy items when the game gets up to elk in size, or above.

I'm waiting on a 7mm Dakota right now; if it shoots them, the only bullet I'll need to use for anything is a good 160 at 3200+.

Handy perhaps,but totally unnecessary.

Just in case this post got missed the first time...

Stubble: Yes, I know you like 140 TSX. Bullets have changed the equation somewhat...I am not a Barnes fan at the present time.

I'm in DC at the moment. I'll post when I get back.

Crow,

I don't disagree with the ballistics surrounding heavy vs light weight bullets and have no need to shoot 700 yards. The difference between a 140 TSX and a 175 Partition is less than 4" at 500 yards, 1.4" at 400. The question we're tap dancing around is reliable expansion, not trajectory. At 500 yards, the 140 TSX is moving at 2050 ft/sec, the 175 2215 ft/sec. Here's the difference between your position and my current thoughts: I know the Partition will expand to 1.5 x its starting diameter at 2200 ft/sec, I have concerns about the TSX, regardless of what Barnes says. My experiences seemingly contradict common thought on the lightweight bullet theory.

I do find it curious that many/most folks shoot 180's (many Partitions) in 30 cals for elk. I'd venture that the "Standard" 30 cal load is a 180 Nosler Partition in a 30-06, 300 WM or WSM traveling between 2750 to 3050. A 175, 7mm shoots just as fast as 180 grain 30 cals, has a higher BC, and slightly less recoil. Somehow a 175, 7mm is hugely different than a 180, 30 cal. I'm thinking not.

I'll post a pic or two of unexpanded TSX's and could re-post my experience with my 2 deer from last fall. I realize I'm in the minority but I can't explain my TSX experiences. Suffice to say, the Partition has been killing stuff for 50+ years. Again, I'm not throwing the TSX under the bus. I still shoot them. It's the nagging question in the back of my mind that I can't definitely explain.

Well, I think the fact of the matter, as has been stated before, is that any bullet will eventually fail. Yes, my friends, even the beloved partition has failed (if by fail, we mean that it has behaved in a way other than how it was designed to), and will undoubtedly fail again. The TSX is no "wonder bullet," nor is it supernatural in design or manufacture. It will also fail from time to time (again, it will behave differently than it was designed to, regardless of whether or not it kills the animal it's shot at).

I just picked up a box of 7mm 140 gr TTSX's today to test out. That may be your answer bwinters, flat shooting AND supposedly even more reliable expansion than the standard TSX.

Bwinters,

I don't use the barnes TSX because I've seen such awful performance out of their original X bullets. Many say they've improved the TSX design, I'll take their word for it but I'm not going to be the guinea pig when there are so many other excellent bullets out there. If you're not confident of the TSX expanding at long ranges then I'd personally switch to a bullet I have confidence in instead of jumping through hoops to make that bullet work.

I think there have been hundreds, if not thousands, of guinea pigs to test the TSX's on, you're not the first, believe me.

Fair 'nuff.

Well b,
I know a hard-headed gun nut when I see one.

Please copy this intire thread to a Word document or something; save it or print it out for future reference. Go out and get yersef' a $1500 (or so, with good scope, etc) STW, load 'er up with 175s and kill some stuff. After about three years, read this thread again. You may be surprised at what was written.


Good luck on your STW project.

I read something addressing why some TSX's aren't expanding. I wish I could remember where...Handloader magazine maybe? Anyway, it said that if the HP tip hits just right, instead of opening up, the HP get's pinched shut, therefore it doesn't expand like it should. Is this why the tipped TSX's came out? I don't know, but it's interesting food for thought.

I�ll apologize up front for the length of this post���� It�s bound to stir a few comments so I�ll try to explain my reasoning in 2 posts.

I found some unexpanded TSX�s but not the ones I was looking for. I have at least 2 more that look like the unbent TSX in the pics. I had 3 unexpanded, unbent TSX�s, laying loose on my bench before I moved but have obviously been put some place for safe keeping. I�ll find them when I fully unpack ( I moved ~ 18 months ago and have not fully unpacked all my loading stuff, pending finishing my basement this summer/fall/winter). A couple of things to note. The two pics are the left and right side of the same bullets.





I�ll answer a couple of questions before they get asked:
A. These bullets show no signs of hitting anything hard � no marks, no scratches, no flat spots - nothing. In fact, they retain a sandblasted texture from the silt/sand dirt pile they were shot into. You can pick up the texture in the pics. I can�t recall ever finding any rocks in this pile even though I�m sure there is � somewhere.
B. The �dirt� pile is found in an abandoned sand pit behind my previous house. The pile�s been abandoned for 20+ years. The pile in question is ~ 50 feet long, 12-15 feet tall and was placed by man � likely some sort of washing operation. The material is a very fine grain sand to silt for those geologically inclined. I�ve shot hundreds of bullets into this particular pile.
C. I had this happen on at least 2 different occasions with 2 different boxes of 168 TSX�s.

Empirical observations from shooting into this pile for 5 years:
1. The only bullets to ever display weird behavior are TSX�s � almost exclusively early 168, 30 cal TSX�s shot at high velocity (3000 � 3200). I�ve shot Noslers - Partition Gold and regular; and Bal Tips, Sierra�s, Hornady, Speer � Hot Cor and GS, Barnes � TSX and original. Only high velocity TSX�s displayed this non opening behavior.
2. Shot at velocities of 2800 or above, only the Partition�s and Barnes stay together. All others range from 20-30% weight retention to large pieces of shrapnel.
3. At velocities below 2800, most stay together although still lose a lot of weight, except the Speer GS. They seem to retain 65-70% when kept below ~ 2700.

Possible explanations for TSX behavior:
� Conversations with Ty Herring (Barnes) indicate the bullets need �something� to start them opening, most likely some form of liquid � muscle, guts, something. The issue may be that I shoot into the pile during spring/summer/fall months. It is possible that the �pile� was not moist enough to initiate opening, leading to the bends. I have other TSX�s that are mushroomed but also bent pretty good. This is the main reason why I�ve never posted these pics before, even though this all happened 3-4-5 years ago, when the TSX came out. I also think the opening initiation failures I experienced is why Barnes came out with the TTSX. The tip will now initiate expansion.
� The early TSX were slightly harder than they are now. I�ve not had this happen since, despite shooting many TSX�s in 0.257, 0.284, 0.308, 0.338, 0.416 calibers into the same pile.

TSX's taken from the same lots as the unexpanded, note some are bent:

Last edited by bwinters; 04/03/08.

Part 2

Game experiences:
� 4 years ago I shot a doe in KY with a 140 TSX from a 7mm RM using 68 grains of IMR 7828, MV = 3130. The shot was ~ 75 yards dead broadside. At the shot, the deer took off running like nothing had happened. I tracked her ~ 100 yards using scuffed leaves and general direction of travel as it was a fairly open woods. She was dead when I found her but I had to search for an entry and exit hole. Double lung hit. Damage inside was fair but the holes into and out of her were dime size at best. I chalked that one up to �Stuff happens�.
� I shot 2 deer this past fall with 100 TSX�s from a 25-06 using 54 grains of IMR 4831, MV 3325. The first deer was ~ 60-70 yards, slightly quartering to me. I shot it behind the shoulder, the bullet angled through the near lung, just caught the rear of the far lung and exited out just forward of the diaphragm. She ran ~ 15-20 yards stopped and stood, after ~ 1 minute she lowered her head but stood there. After ~ 2 minutes she laid down heavy, not falling down, laid down. After ~ 1 minute she rolled down the hill a couple of turns, kicked a few times and died. The whole episode took 3-4 minutes. I found some blood but not a lot. The damage inside was not extensive � a dime or smaller size hole through the lungs.
� Deer number 2 was shot a few days later right behind my house at a distance of ~ 140-150 yards. She dropped at the shot. I shot her high, through the shoulder blades, severing her spine, killing her instantly. I cut her up the following day and was disappointed with the damage done by the TSX. The shot went through both shoulder blades. They had a dime size hole through both blades but did not break either � just a neat hole you couldn�t stick your pinky in. Internal damage was nothing to write home about. Pics below. Note the shoulder blade is in 1 piece but did have a crack in it.

Last edited by bwinters; 04/03/08.

Thanks for taking the time to hang the pics. Appreciate it much.

I'd rather use a 140-160 Swift Aframe than anything else mentioned here so far.Concerns about reliable expansion and broad enough frontal area just go away; weight retention is higher than the partition,on a par with the TSX,and they shoot sufficiently flat for any rational use,IME as flat as a partition when started at the same velocity.

They MAY not penetrate as far as a TSX but they will penetrate as deep as you'll ever need.A 140 started at 3300-3350 from the STW will be a bomb; ditto a 160 at 3250-3300.

I can't think of anything except brown bear on this continent that I'd hesitate to hunt with these loads.

Great photo story with shot bullets, I always enjoy seeing them. One thought is they may not be opening up due to the medium, in this case, dirt and how it affects them when they strike. Its unfortunate you didn't find any of the ones you shot deer with to see how they opened. I found a 30 cal Hornady SST similar to your TSX's at my range in the dirt:



I can't say velocity or any other details as I wasn't the one who shot it. Experiences are hard to argue against, but my impression (and this is JMO) is that deer are fairly light framed and IMO, the best bullets for them are simple cup and core, I'll save the tough premiums for game that they're better suited. The exception to me being the NP. Now I have seen deer that have had massive damage done by TSX's but like I posted earlier on an article on how the HP gets pinched shut when it hits just right, preventing proper expansion...is this why the TTSX came out? I don't know but I'll sure be interested in your results with them and the differences you see.

I'm one of those people who tried X bullets - and tried and tried and tried. I'm also like some others who probably won't go back now even if the TSX works well. The Nosler Partition works very well though shots of recovered bullets are never pretty due to the Nosler design. I have no doubts the TSX is as good as many have reported but with the Partition working so well my reaction now is, "Why bother?". I had similiar problems with Sciroccos - could never get them to shoot really good though they were not as bad as the Xs. Tried Accubonds and never looked back. Again, it could just be my particular rifles. Somebody out there is probably putting Sciroccos through one hole with their rifle.