7mm-08 - 139gr Horn GMX

Deer_Slayerwis · Rookie Member Joined: Aug 09, 2010 Posts: 2

New to reloading 7mm-08 requesting data for smallest groups..

I will be reloading new Rem cases, Win WLR primers, Hornady 139gr GMX bullets. Recommended powder min/max.

gelandangan · Posted: Sun Aug 08, 2010 9:49 pm Post subject: Re: 7mm-08 - 139gr Horn GMX

Uh Oh .. another deer slayer ..

Gday mate.. welcome to this fine site Smile

Never use a 7mm-08 so I cannot comment.

Just hang in there.. Someone would pipe up soon enough.
In the mean time, grab a beer and sit near the fire...

So, what kind of deer do you slay? where and how?
Cmon tell us a some story.. you must have quite a few

slimjim · Posted: Mon Aug 09, 2010 5:29 am Post subject: Re: 7mm-08 - 139gr Horn GMX

Each rifle has its own charactor so what powder/bullet combination that provides the smallest groups in one rifle won't necessarily work the same in another. I load GMX bullets in my .270. They have been the most accurate of all the bullets I've tried including match bullets. Hornady designed the bullet to load the same as their lead-core bullets. The two bands reduce pressure to be similar. Try the Hornady website for load recommendations. They list a 139gr Hornady bullet. You will have to go through several selections to get there. I have heard you may run into max pressure signs about 0.5 grains sooner so be observant. Consider using the OCW method to determine the best load for your rifle.

hodgdon.com/

slimjim · Posted: Mon Aug 09, 2010 5:30 am Post subject: Re: 7mm-08 - 139gr Horn GMX

here is the OCW post

www.huntingnut.com/ind...hlight=ocw

shrpshtrjoe · Posted: Mon Aug 09, 2010 2:21 pm Post subject: Re: 7mm-08 - 139gr Horn GMX

Welcome to the HuntingNut Howdy

Hopefully you will have better luck than I did. I had a 7mm-08 a small ring Swedish Mauser sportorized by Kimber never could get that damn thing to shoot.

Joe

chambered221 · Posted: Mon Aug 09, 2010 3:50 pm Post subject: Re: 7mm-08 - 139gr Horn GMX

Welcome to Hunting Nut !!!

I've been using Varget with a 120gr. Ballistic Tips that have produced 5 shot groups around a 1/2MOA. (100 yards)
Other powders that have worked well for me have been; H414, W748 and IMR4064.

slimjim · Posted: Mon Aug 23, 2010 5:45 pm Post subject: Re: 7mm-08 - 139gr Horn GMX

Deer_Slayerwis, how did your trials go? I'm interested in how others are doing with the GMX bullet.

Glenn1022 · Posted: Sun Aug 29, 2010 11:40 am Post subject: Re: 7mm-08 - 139gr Horn GMX

I use a TC Encore with 7mm08. IMR 4064 between 41 to 44gr all did well with Nosler 140gr ballistic tip. All would put you in 1moa @100yds in my rifle. I have had great success with IMR 4064 in several rifles as well as IMR 4895 and 4350 are good powders to try as well. I use CCI large rifle primers with Remington or Winchester brass.
I tried Hornady 139gr and they shot like crap in my Encore but shoot great in my brothers rem 700.
So...with that said, it depends on your rifle. Every gun is like a person, some are wild, some are lame and a rare few are great athletes. The loads I listed above should give good starting point but you will have to try each for yourself to see.

NOTE...44 gr of IMR 4064 are considered max in some manuals and 41 gr max in others. Always start low and work your way up. I am talking from personal experience and you do not want to ruin a good gun or injure yourself.

Hope this helps. I have allot of loads worked up for 7mm08 and medium burning powders seem to do well with 120gr to 140 gr bullets. The three I listed above have given me the best results.

fnuser · Posted: Sun Aug 29, 2010 4:09 pm Post subject: Re: 7mm-08 - 139gr Horn GMX

Its interesting that you mention imr4064 it is often overlooked as people are attracted to the velocity offered by newer or slower powders just for kicks one day I loaded up a bunch of .270 Win. and .308, and 30-"06 cartridges and shot them over a chonograph velocities for these three cartridges differed less then 5 f.p.s., the .270 less then 3. This is remarkable and not easy to achieve with any other powders I have played with. sometimes this translates into accuracy, not always. Just an interesting footnote. Thought I'd share. Anyway I just hadn't heard anyone brag on IMR4064 in awhile and it triggered that memory.

slimjim · Posted: Sun Aug 29, 2010 4:17 pm Post subject: Re: 7mm-08 - 139gr Horn GMX

fnuser wrote:

Its interesting that you mention imr4064 ... shot them over a chonograph velocities for these three cartridges differed less then 5 f.p.s., the .270 less then 3. This is remarkable and not easy to achieve with any other powders I have played with.

Thanks for the tip. Sounds like a great powder to use for long-range applications where velocity variation leads to poorer accuracy.

44marty · Posted: Wed Sep 01, 2010 2:01 pm Post subject: Re: 7mm-08 - 139gr Horn GMX

IMR 4064 also has given me the smallest variation in velocity in my .204

Still, I get results very nearly as good with IMR 3031 and IMR 4895, with both giving increased velocity over the 4064.

IMR 4064 is listed as the giving the best accuracy for several different chamberings in a few different manuals. I use only IMR 4064 for both my
K-31's and get great results - much better than I was getting with Varget.

slimjim · Posted: Sat Sep 04, 2010 12:37 pm Post subject: Re: 7mm-08 - 139gr Horn GMX

I love these GMX bullets - they seem to shoot great every time I load them. Took 47.0 grains of IMR 4064 to the range today and shot a 5-round group at 200 yards. Looks like I might have dropped one. Basically, a 1/2 MOA group. Hodgdon listed 47.3 as the max. There was absolutely no signs of pressure so I may step it up some and see what she does. As soon as I get the velocity data off the computer, I'll post it.

slimjim · Posted: Sat Sep 04, 2010 3:18 pm Post subject: Re: 7mm-08 - 139gr Horn GMX

IMR 4064
2842
2861
2649
2861
2842

average = 2851
std dev = 9

This is a great SD but does not offset the velocity loss from my IMR4350 load.

average = 3048
std dev = 28

Will have to investigate a higher loading for IMR 4064.

Deer_Slayerwis · Rookie Member Joined: Aug 09, 2010 Posts: 2

Well i started my first test...

Browning X-Bolt 7mm-08
Rem cases
WLR primers
139 gr Hornady GMX bullets
37.5 grs Varget
----------------------------------------------------------------------------
25 yd = .75 in
100 yd = 3.0 in
---------------------------------------------------------------------------
Trying to find sub .75 in 100 yd ...

Any pointers????
looking for the accuracy load...

slimjim · Posted: Sat Sep 04, 2010 8:02 pm Post subject: Re: 7mm-08 - 139gr Horn GMX

Deer_Slayerwis wrote:

Well i started my first test...

37.5 grs Varget

Hornady promotes that you can use the same load data for their lead-core with the GMX. Hodgdon list this load data for Varget.

139 GR. HDY SP
COAL 2.800"
Min load 40.5 gr 2721 fps 44,700 CUP
Max load 43.5 gr 2877 fps 50,000 CUP

I believe you load is well below minimum and you may be getting unreliable powder ignition.

I would suggest loading up 3 each of 41.0, 41.5, 42.0, 42.5, and 43.0. Shoot these and check group size and POI to find the sweetspot. I don't bother with the minimum load as it is usually a wast of time and components for me. I also find my best group closer to max load. If the group size is decreasing with the 43.0 load, then load some higher and test them.