Home Forums Reloading Big Game Rifles Hornady CX vs GMX bullets

Ok, I'm a laggard. I know that. But just when I'm about to introduce the GMX to my rifle barrels up pops the CX bullet. Damn.

Hornady doesn't bother to compare / contrast (yet?) the two bullets on their website, so my SWAG is simply guilding metal vs copper alloy?

So my questions would be:
- which metal requires a higher impact velocity to perform to design? GMX or CX?
- are the two bullet designs close enough that I can use GMX load data with the CX?

And I thought my winter would be slow....

So I found a short video blurb from Hornady that compared GMX to CX and the jist of it was the CX would retain enough expanding velocity (2000 fps) about 100 yards further than the GMX.

Oh, and this is interesting - the GMX product line has been removed from their website.

I guess that simplifies things a bit....

Interesting that there are no 130 or 150 gr. 30 cal. bullets.

I'll probably start by trying a box of their superformance ammo to see what gives. My rifle liked the GMX version going at around 3000 fps and did not like the outfitter version using the GMX which was going slower.

If it stays true to form then I'll buy some CX and load up...

From what I gather the CX is to GMX what the LRX is to the TTSX line on the Barnes line. Higher BC's and better opening qualities at distance. It looks to me like Hornady may replace the GMX line with the CX line while Barnes may keep both lines. Please don't take this for gospel as it is nothing more than my opinion.

Todd

Both bullets are a "copper alloy"

"Gilding metal is a form of brass with a much higher copper content than zinc content. Exact figures range from 95% copper and 5% zinc to “8 parts copper to 1 of zinc”

Does CX stand for CovidvaX?

My thoughts mirrored yours, Justahunter. I've seen no indications yet that the CX will expand at the low velocities attributed to the LRX. Puddle mentioned 2000 fps. It'll be interesting to learn more as info becomes available.

The 90gr 6mm version looks interesting. Will have to see the twist requirement. I do think they need a 120gr 7mm and 130-140gr .30 cal.

Now that's interesting!

Anyone got range reports on these yet?

I've visited the usual suspects. None to be had. Yet.

From what I gather, CX has redesigned grooves and ogive to give it a higher BC. Also uses the heat shield tip.

I do not know about bullet composition, but would assume it is the same as GMX, but do not know for certain.

Edited to add:
Confirmed with Hornady, same metal composition.

I'ts a new product for 2022, I doubt there is any out yet.

Hornady told me they have been loading them in their factory ammo. But did not know about component availability.

From some research it appears bc are actually lower advertised than the old GMX bc. Maybe just corrected BCs and renamed? Relief groves are redesigned some.. but a 2000fps min impact doesnt seem like an improvement to me?... if bc didnt go up, maybe they believe their new groove will increase velocity/decrease pressure to get the extra 100yds of preferred expansion?

I'm curious as well about the twist rate required for the 90 grain 6mm bullet. The 80 grainer has 2 groves and the 90 grainer only has one.

They're next in line for developing a load in my .26 CM, right after I finish:

- 140 gr. Partition
- 140 gr. Weldcore
- 130 gr. Scirocco

then the 130 gr. CX (and perhaps the 120 gr. TTSX as well)

It has been my experience that higher BC long range bullets are harder to get to shoot accurately. My Barnes 6.5 120gr TSX/TTSx, excellent accuracy. Try the 6.5 127 LRX & accuracy is dismal. Same results with Nosler . Great accuracy with their 6.5 140 gr AB bullet, but terrible results with their 142gr LRAB. Have had similar results with other so called long range bullets. It appears there is less surface contact between the bullet & the rifling.. Which results in less stability.