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