Home Forums Reloading Big Game Rifles Reloading Kimber Montana 7mm08

Howdy all,

I’ve been lurking a bit, collecting equipment over the past few months and I’m finally ready to get started developing a load for my Kimber Montana in 7mm08. It has a 22” barrel with 1:9 twist. I’ve had fun shooting different factory ammunition, have taken a few Sitka Blacktail deer and can get near MOA, sub MOA (and some def not MOA) with most factory ammunition but my goal is to squeeze the most accuracy out of this rifle, learn more about my rifle, hopefully get to 2/3 MOA and develop 1 or 2 loads for hunting Sitka blacktails, mountain goats, elk, (sheep?) and paper from 100 to 500 yards.

I recently got my hands on 6# Ramshot Big Game and picked up a couple hundred bullets, 140gr TTSX and 150gr ELDX as well as 100 Lapua cases and CCI 200 and 250 primers. I also picked up a large assortment of powder and bullets from a pal that was moving and the movers wouldn’t take his powder.. so I also have the following:



H414
Varget
CFE223
H1000
Benchmark
Retumbo
IMR 4064
W760



18 - 140gr TSX
16 - 150gr TSX
9 - 150gr Nosler Partition
25 - 140gr Nosler Accubond
19 - 150gr Sierra Game King
124 - 168gr Berger VLD

I'm kinda saving the TTSX, ELDX and Big Game until I feel confident in my reloading process so right now I'm getting familiar with the process and equipment.

For my first reloads I decided to go with a ladder test with 150gr GameKings over Varget. I used once fired factory brass (as I figured I'd damage some cases while reloading and didn't want to sacrifice my Lapua cases just yet - good decision!) I'm using a Redding FL die set, Forster CoAx press, PACT electronic trickler supported with RCBS M500 scale.



I'm glad I hit paper with the first round, adjusted scope down and left it there for all remaining shots.

I had extra bullets so I kinda just guessed I would want more data for charge weights in the upper middle of my chosen range so I loaded up some extra rounds.



As these are my first reloads, I am wary of the first bunch of rounds. At first I was trusting my PACT but then started verifying charge weights with the mechanical scale, good thing too! The PACT would consistently charge 1/10 or 2/10 over my intended target charge. So I would have the PACT charge a few tenths under my target, then trickle the last few tenths by hand using the mechanical scale. I feel pretty confident with the mechanical scale. Some thoughts about the PACT: The supplied calibration weights are 20GRAM and 50GRAM.. but when charging 40GRAIN, wouldn't it be better to calibrate with weights closer to the desired charge weights?? Also, the guy I bought it from had sent it in to PACT to have the software updated to the faster mode, so the faster mode could be why it's overcharging, the scale can't keep up with the dispenser? Kinda similar with the mechanical scale, it can weigh up to 500GRAIN, but if it were designed to only measure up to 100GRAIN, couldn't we get a more precise measurement? Just thinking out loud here.

I am pretty excited about the results tho. Velocity is recorded with a Magnetospeed Sporter. I see small ES and SD numbers, so if I were intending to find a load with the Game Kings, I see some ranges in there I would get more data for.

I also loaded up the 150gr Partitions. I found some load data that suggested 37.0gr Varget was ideal for accuracy and so I loaded up 0.5gr under and over. My results are consistent with what I had found in the books.


36.5gr lower left, 37.0gr upper right, 37.5gr lower right



I have my next batch of rounds loaded up, 150gr TSX over 43.8-45.8gr H414 with CCI200, 3 loads each at 5 charge weights, BTO 2.2905" which is 050" off the lands in my rifle. Just have to go shoot them!

I’ll be posting back with hopefully more results than questions.. this is a priority for me this month, along with flossing salmon and going out on some recon missions to find some 4 legged critters to hunt this fall. Feel free to offer suggestions, tips, loads.. there’s many possibilities!

Whew !!!!!!!!!!!!!!!!

There's not enough consistency in any of that data or groups to make any sense of it or to get any real direction..................& yet you say the gun is <1/2" MOA with factory ammo???? And now you are going to switch bullets & powders for another series of tests???

Varget is usually an accurate powder in the 7-08, all other things being equal & good, but you're missing H-4350 & RL-15 which are both excellent & proven powders in that round.

When I do load work-up, I usually use Nosler BT's across the board as they are almost always accurate in most calibers, most guns will shoot them well, if they are going to shoot anything at all well, & they are cheap & readily available. I usually keep all the bullets at .010"-.015" off the lands for starters.

Pick 2-3-4 powders that you want to work with & proceed to refine loads down to one, or at most 2, prefferred powders, then test the bullet that you really want to use for confirmation & final fine tuning of charge & seating.

Also, concentricity of the loaded rounds is IMPORTANT; I have consistently good results with Forster's BR seater (no need for the micrometer head unless you JUST HAVE to have it).

Good guns are usually not overly finicky; bad guns are & they go down the road real quick like for me.

Here is a target with some load work-up in a 7-08 Ti with 3 different powders, one bullet.............I pulled one shot out, but you can see that the other 8 rounds are one big ragged hole. That's not a powder finicky gun, & it shoots much the same with other bullets.

MM

Hey, thanks for the comment. I'm new to interpreting data so sorry if our interpretations are different. I was really just looking at the velocity data, obviously I wasn't shooting great groups. As I mentioned, I'm getting familiar with the process of reloading right now, not diving in too deep into developing a load until I feel confident I've worked out some bugs in the process. I did pick up a Forster BR die but the darn thing gouged my bullets upon seating. I looked inside and theres some tooling marks, so I'm gonna have to send it in to be cleaned up.

I seated the Game King to 015".. I think the Partitions were 020".. or close to.

Nice target! Holy smokes, something to aspire to. Hopefully I'll get there. Unfortunately there's no 7mm Ballistic Tips in Kodiak. TTSX, SST, ELDX, Partition, Accubond, Accubond LR

As I said, I came across a random assortment of powder and bullets, just doing some loading for now. I plan to do as you say and narrow it down to a couple powders and a couple bullets.. I said all this in the original post..

I've had very consistent accuracy from both the Barnes bullets & the Nolser AB's, but they are just quite a bit more expensive than NBT's for load work-up, but I guess you have to use what you can get.

I've not shot Bergers of any sort in the 7-08.

At any rate, good luck.............you can see the powder charges for Varget, H-4350 & RL-15 on the target, so I hope it helps you get up & going.

MM

Varget and IMR4350 was too slow for me with the 140s. Varget was great with 120 grain NBTs, though. Big Game and RL16 gave me the best accuracy and speed with 140 Partitions/Accubonds.

Big Game, 140 grain Partitions, and WLRM primers have proven to be the bees knees in my 7-08.

As far as price, I don't think I've paid more than about $20 for Accubonds.

Hey N2, what speeds did Big Game and RL16 give you with the 140s?

How different are WLRM and CCI250?

47.5 grains Big Game
140 Partition or Accubond
WLRM
2.805” OAL
I get 2870 FPS or so from a 22.4” Tikka, 1-9.5”

Kills elk








46.2 grains Big Game
150 ELDX
WLRM
2.805” or so
I get 2790 FPS or so

It kills elk, too



I use Hornady Custom Grade dies. If you decide on the ELDX, buy the ELDX-specific seating stem from Hornady.




Partitions:







P

RL16 gave me 2800 fps. Big Game gave me 2850 fps.

Varget gave me 3000 fps with 120 grain NBTs.

All in a 20" barrel.

Alrighty, I hit the range today.

150gr ELDX
Ramshot Big Game
CCI 250
Lapua brass
BTO 2.156"

I did a ladder test from 44.4gr to 46.2gr, 2 loads at each charge in increments of 0.2gr at 100 yards






I'm thinking about how to proceed from here. I either want to proceed with loads that showed good accuracy (I know 2 loads isn't a large sample size, but it's what I have) or with loads that have a small SD in velocity. Looking at the target, I like 45.0gr (#4), 45.4gr (#6), 45.8gr (#8) and 46.0gr (#9). These have very little vertical dispersion; it was quite windy today, so I'm not as concerned with horizontal dispersion..

45.4gr (#6), and 45.8gr (#8) also have the smallest SD..

What are your thoughts? Thanks

PS Oh, I'm trying to keep my range trips limited to 20 shots, so I'm thinking about either strings of 3, 4 or 5 rounds

Load nine.




P

I would procedure thusly. Clean the chit out of it. Load 10 #9s. Shoot 5 cooling completely between shots. Clean the chit out of it again. Shoot the other 5 without cooling between shots. I'm not saying rapid fire. Just work them through. Out of the mag too. If they feed and follow suit with your sampling of two,your done.

If you want to save yourself time and money pick one bullet and one powder and go from there. ie, a 140gn Nosler Accubond with RL17 or Big Game. Testing different bullets of varying weights with a variety of powders create more headaches than it's worth in my opinion.

Is your rifle epoxy bedded with a free floated barrel? If not, that's the first thing to get done.

And as Otter6 says, cold bore shots (even in a bedded rifle) are best for determining an accurate load. In winter that's easy to do, on a hot summers day it's almost impossible because the barrel never cools down quickly enough.

Load 6

Kimbers come pillar bedded. Barrel floats. I thought about bedding the recoil lug, but didn't wanna screw anything up.

Kimbers are bedded to a slave action, not the particular one you get.

Ok, so during my ladder test posted above the POI's are backwards, higher velocities hitting lower than lower velocities. I've read that's because the bullets are below the line of sight at 100 yards or something? Or barrel harmonics..

So load 9 POI was 3" high on my target, my scope elevation was on 3, so i dial down to 0 and shoot.. POI moved UP 3"! And my scope is bottomed out..

I have 20 rounds made up for today and I'm hoping to figure out how to zero my rifle.. Any thoughts? I can try shimming the front scope ring.. but I'm gonna troubleshoot the scope settings and mounts first..

If I dial UP, how would the POI move? I need to draw this out..

Sounds like something is up with your scope or mounts. I wouldn't do anymore testing with that setup until I figured it out.

What scope?

False alarm on the scope issue... I took the magneetospeed off and all was right in the world again

I think I'm done, 0.60"



Kimber Montana 7mm08
Nightforce SHV Scope
22" barrel
1:9 twist
150gr ELDX
46.0gr Big Game @ 2784 FPS
2.156" BTO
CCI250
Lapua Brass

Used a ballistic app to take it out to 500yard and hit 12" plate first shot