Home Forums Reloading Big Game Rifles Hornady GMX (lead free) Prelim Report

After a long wait, I finally got my hands on a box of the new Hornady .284 139g GMX lead free bullets. I was anxious to see how they compare to the Barnes 120g and 140g TTSX.

The first noticed that the GMX is constructed with Hornady's familiar secant ogive, while the Barnes uses a tangent ogive.

I then weight sorted 10 random bullets:

138.4g - 3
138.5g - 3
138.6g - 3
138.7g - 1

Here is a pic of various 7mm bullets for comparison, from left to right (1) Barnes 120g TTSX, (2) Barnes 140g TTSX, (3)Hornady 139g GMX, (4) Hornady 154g Interbond, (5) Nosler 150g BT, and (6) Nosler 140g BT.



As you can see, the GMX has quit a bit more bearing surface than the 140g TTSX.

It may be a while before I get to the range, but I'll report my findings when I get em. I've been getting good results at the bench with the Barnes 120g TTSX in my 7-08AI, but its nice to have another option.

Wow...that sucker is long and not too many bands.
FWIW I recently played with the 130ttsx in my 300 win mag. First thing I noticed is they have another groove more than the old tsx.
I worked up a load to 86.5 I7828ssc with the 130ttsx and for a comparison shot them side by side with some moly coated nosler 125 bts'. Without having pressure testing equip and using a chrony as a "comparison tool" I think I can say pressure was virtually equal with the ttsx running 3560 over the chrono and the bt running 3580. This was win brass, a tikka t3 with 25" barrel and lots of freebore and no pressure signs or feeling of primer pocket expansion on the next loading. DISCLAIMER: THIS GUN HAS LOTS OF FREEBORE....WORK UP IN YOUR GUN!
Anyhow I like the progress barnes is making with the fine tuning of the grooves.
It might be fun for you to possibly pick some medium loads and run some of the above bullets accross a chrono for a comparison.
BTW for what it's worth 5 shots with the ttsx went under moa to 200 yds...that bullet has been accurate in every gun I've tried them in so far. Am still playing with them in my 308 and '06 to see how fast they will go but I think they will "redefine" some 308 cartridge performance.

Should stop blabbing here but one other thing I noticed is that the grooves on the hornady are at the top of the bullet. Seems like mono bullets have a tendency to spike pressure when seated near the lands. Could it be this helps get the bullet through that "transition"? Fewer ridges should help bc...hmmm....are they onto something??

how were they price wise in comparison to Barnes?

I wanted to try the 7mm GMX but Hornady told me it would be a while before they were produced.This was last spring. Congratulations on getting some of the first ones. Too late for this season for me.

I opted to go with the 150 nosler E-tip in my 24" 7 Rem mag. Moly coated and seated very close to the lands didn't produce any pressure issues. First used some moly coated 150 nos bt to determine approximate velocities/pressures with the new RL-17. Ended up with the ballistic tip and E-tip liking the same seating die setting and same powder charge. 150 nos bt 3275, E-tip 3285.

Be sure to report on their accuracy and later (hopefully) your report on their performance on game.

Bass pro shops have the gmx in stock in Birmingham. They run 5 or 6 $ less than tsxx's if I remember correctly. John

Sure looks like a lot of bearing surface length on the GMX...........gotta believe that's gonna require some load charge weight reductions.

But if it's a gilding metal bullet instead of pure copper, that would mitigate a bit of the bearing surface issue vs same/same in a copper bullet.

Let us know how the perform at the range; very interested.

MM

Kracky: The 120g TTSX shoot very well in my 7-08AI at 100, yards as well, sub 1/2". I need to take them out to 2-300 and see how they hold together.

Interesting theory on the bands, but my guess is Barnes figured out that the bands are required to reduce fouling and pressure. Hornady could not come out of the gate and copy Barnes, so they opted for a couple less groves. I'll see how they shoot and then make the final call.

I ordered these from Cabela's many months ago, and I think I chucked the shipping invoice. Like Montanaman said, about $5 less than the Barnes TTSX if I recall.

I've been buying the 150 grain .308s for several months from Sportsman's Warehouse here in CO. They shoot very well in my Montana in 308 Win with Big Game and Re 15. I'll try them out on elk this November.

Shallower grooves on the GMX as well. Any idea what the base to ogive length is on the 140TTSX vs the GMX?

I can measure with caliper, but I don't have an ogive guage so measurement may be approx.