Home Forums Hunting & Shooting Ask The Gunwriters Pressure CX v LRX v TTSX

Does anyone have any ACTUAL EXPERIENCE with the relative pressures generated by the CX bullets compared to the Barnes LRX & TTSX? I am loading .277” 130’s.

Please no speculations.

RinB
Actual Experience data varies depending on who you talk to. Some measure Actual Experience with adjectives and adverbs. Other like myself measure it in PSI.
Charlie

Mr Sisk
I have used many of the LRX and TTSX in the 270W and over a long period time wise. Interestingly I push loads less with each year of experience. I suspect the CX bullets will generate more pressure as the ETips seem to do. However I don’t like to guesstimate or speculate.
Thanks,
R

Curious on this as well.

My rifle really likes the 129 LRX under H4350 or H4831. Interestingly, I too was looking at the CX. Hornady doesn't distinguish load data between cup and core or monos in the 130 - at least in the app. Their H4350 and H4831 max charges for the 130 CX match what I've done with the 129 LRX - but to RinB's question, are pressures the same? The 129 LRX and 130 CX seem to look the same with 2 grooves. The e-tip only has 1 groove but I didn't notice any pressure issues in the 30 cal 150 version in my 308 or 30-06.

Rick,

Despite your admonition about "speculations," there are certain basic principles involved in monolithic rifle bullets. First, pure copper monos such as Barnes tend to generate more pressure than those made of harder copper alloys, such as gilding metal--the copper/zinc alloy used for most rifle-bullet jackets, which is usually around 90% copper and 10% zinc. This may seem counter-intuitive, but the softness of copper tends to result in more friction than harder gilding metal. (Nosler E-Tips are gilding metal.)

The other general principle is the more grooves in the bullet, the less friction and hence lower pressures. The original E-Tips didn't have any grooves, but eventually Nosler put a single groove right about where the ogive enters the rifling, which reduced peak pressure a little, and also made them easier to get to group well.

But any comparison in pressure in the same would also have to involve making sure the ogive is the same distance from the lands.

Wouldn’t the practical approach to understanding relative pressure differences - simply be to shoot each bullet over a chrono with the same charge weight and look at the velocity difference? Seems straightforward.

I've seen comments equating TTSX and CX material, but what I've read on their related websites is the TTSX is 'pure' copper and the CX is copper alloy.

Now, I've read another vendor's marketing material saying their 'pure' copper expanding bullet is 'more pure' (?) than Barnes, and AFAIK Hornady has never mentioned what is the mix of their copper alloy CX.

Just sayin' ...

That may or many not indicate relative pressure. As I mentioned above, the distance to the lands also makes a major difference. Now, you can measure that in more than one way, but monolithics tend to group better when seated farther from the lands that lead-core bullets--and different monolithics tend to group better at different distances as well. Have generally found that E-Tips require deeper seating than Barnes TSX/LRX bullets.

The easiest way to approximate the same pressure is to use a powder charge that gets about the same muzzle velocity as pressure-tested data, though that will also vary with barrel length.

For what it's worth, Hornady Tech support told me the CX bullet is an alloy that is nearly pure copper. He said about 99% Copper.

He also said that you could use the older data from GMX bullets with the newer CX bullets.

He said the GMX and CX were the same alloy,the only difference being the polymer in the tip and the grooves were very slightly different. I think the grooves in the CX have a radius but that the reloading data is still the same.

That's good info. I've collected my fair share of GMX data in multiple cartridges and it's handy to know they're a jumping off point rather than starting from scratch.

Back from range.

The CX 130 and LRX 129 were shot.
The 130CX used 1.5 grains less powder (IMR4831) than the 129LRX to get to 3000.

Big difference in accuracy. The LRX went around .65”. The CX both handloads and factory Outfitter over 2”.

Not surprising from what I’ve seen from our 270s and other calibers I’ve tried Hornady bullets in. Just not a fan of their products. Try some Hammers along with those Barnes. I have in several rifles and they haven’t failed to put a smile on my face.

Rick,

Have been using the predecessor to the CX bullets, the GMX, for several years. The GMX was essentially the CX without a plastic tip. They've been very accurate, though like most mono bullets seating depth made a difference.

A good example is the 70-grain .224 GMX, which Eileen and I have both used in 1-8 twist .22-250s with the same powder charge. 3-shot groups averaged around 1/2" at 100 yards, and we've taken a number of deer and antelope out to 350 yards with fine results.

Actually, many of the GMX bullets did have a plastic tip. I really liked the .30 cal/110 grain version designed for Blackout speeds. From a 24" 30-30 Contender barrel, I ran them at 2805 fps. They were absolutely deadly on hogs and coyotes and opened much more quickly -- and much wider -- than typical monos. I used them in a mildly-loaded .300 Savage and a .308 WCF as well.

The 110 grain CX that replaced it performs similarly but not identically, either -- at least not in my usage.

Here's a 110 grain GMX taken from a large hog. I'd have to dig through notes for details, but I know I used the 2805 fps/30-30 load and that the distance was around 200 yards.

Never really considered the CX, GMC or Etip. The Barnes work. I have no interest in trying the others.

Bobby,

Thanks for that info. I just checked my 11th edition of the Hornady manual, published in 2021, and many of the GMXs were tipped--but quite a few weren't. Dunno why...but the 70-grain .224s we've been using in fast-twist .22-250s weren't, which is apparently why I assumed they were all "un-tipped."

Will also mention that those 70s have always expanded on various animals out to 350+ yards.

John

I have been messing around with the 100 and 130gr CX out of my 270. I have not noticed any huge pressure differences between them, TSX, TTSX, LRX bullets.

I will say that it always takes more effort to get the GMX's and CX's to shoot as well as the Barnes varieties.

I did have to play with the seating depth on 130gr CX. When I started reloading the Hornady GMX, Hornady suggested start 0.030" off the lands. Worked great.

Fast forward to the 130gr CX's. Started at 0.030, per previous suggestion, not spectacular. Emailed Hornady, they said 0.050" for the CX, groups got even worse. Then I went to 0.015", groups tightened right up. I found a couple of promising loads, just need to get to the range and verify.

For what it's worth, I ran Gordon's with the 0.277 130 GMX, 130 TTSX, 130 etip. For the same calculated pressure, both the 130 etip and130 TTSX used the exact same powder charge to reach a given pressure (~ 62k psi). The GMX used 3 grains less powder across the board to attain the same pressure with the 4 powders I played with - H4350, H4831, Re23, Re26. Velocities in the GMX were also lower than the TTSX and etip.

I'm always wary of trusting pressure/velocty/charge software but for exercises like this, I think it has some merit.

My take away: the GMX/CX seems to generate higher pressures for a given charge weight than the etip or TTSX. I've never shot any GMX or CX in any cartridge so have no first hand empirical evidence to support or refute that statement. I do find it interesting nonetheless,

I will say the modeled charge weight-velocity is pretty damn close to bullets/charges I use in my rifles. This also assumes if the charge weight and velocity match empirical results, the pressure is "accurate". No way you know that for sure without pressure testing.

RinB
Sir I apologize for the smart ass attitude in my post. Seems on the Campfire here these discussions dont go too well. Again I apologize.
I have not performed what I would call a specific test measuring these bullets against each other. However, I have tested a lot of Barnes bullets. Please keep in mind, my test are somewhat skewed as I am using matchgrade barrels with chambers I cut. Chambers make a huge difference. Leade angle makes a huge difference. I have saw a few factory barrels that didnt have any angle at all, just square shoulders for the bullet to engage. And I use carbide piloted reamers. It's really hard to cut a chamber incorrectly with a piloted carbide reamer without breaking the reamer. Its possible, but not likely. Having the chamber and throat aligned correctly does wonders for making pressure more consistent. And seating the bullet straight in the case. Get a cockeyed chamber and about .050 bullet runout, things get interesting pretty quick.
So I said all that to say this: In my experience, I have not saw any pressure issues. I have saw 2500 psi differences when changing from a cup and core bullet to a Barnes, but you can get that much on cup and core when going from one lot to another. 2500 psi is nothing to worry about IF you are loading in a decent range to begin with. A 60000 psi load or a 62500 psi load aint a problem. Now if you are at 80000 psi (a lot of folks load here and dont know it), going to 82500 may get interesting.
And you will find some barrels react differently than others. Kind of like most women I know. You never know what they want.
But back to the original thought: I have not saw any pressure increase or decrease that would make enough difference to matter. But, as I said, my testing could be considered skewed.
Charlie