Kimber mountain ascent 308 win

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.3MOA

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I just took my new Kimber mountain ascent chambered in 308 to the range to attach and sight in the Swarovski 3.5-18x44 I got for it.

P1250473.JPG

I zeroed it through the bore and took 4 shots, then adjusted the scope elevation/windage.

Then I tried out 3 5-shot groups with Barnes vortex TTSX 168 grain ammo (middle row) and 3 5-shot groups with Nosler 164 grain Ballistic Tip ammo (upper row) using sand bags an a small back-pack for support.

Caveat: I always shot heavy range/sniper rifles until I went hunting in November for the first time and decided that carrying around 20+ lbs of SAKO TRG42 in 338 LM may not be the best strategy for wild boar. So I need to work on shooting light rifles.

Long story short, best Vortex group at 100 yards:

P1250475.JPG
The others are worse and they all have 1-2 fliers. Note that I allowed minimum 2 minutes between shots to allow the barrel to cool down a bit.

Best Nosler group:
P1250476.JPG

Next I'll try some Hornady ELD, then settle for 1 type and try to tighten the groups,
then I'll work on load development, with the bullet type that turned out to group best (at the moment it would be a Barnes TTSX 168 gr).

Any suggestions are welcome.
 
There is a learning curve to master a 5-6 lb rifle. I've had a Montana in 308 for about 10 years. They can be mechanically very accurate, but I don't consistently shoot my Kimber as well as heavier rifles. But that is on me, not the rifle. As an all around hunting rifle I like something in the 7-7.5 lb weight class including scope and mounts. That is enough weight to shoot well, but not too much to lug around. My Kimber is 6.25 lbs. currently and is used for those hunts in rugged terrain where keeping weight to a minimum is important. With the right scope they can come in under 6 lbs scoped.

And they seem to be a little picky about liking some loads better than others. But once you find a load it likes you should be able to keep 3 shots into an inch or less. Asking a barrel that thin to hold 5 shots into an inch may be asking too much.
 
Thanks stillquietvoice.
Thanks for your input jmr40, will keep your comments in mind.
 
View attachment 823164 I have your exact rifle in 308 also. When I first shot it I was having some trouble getting it to group. I grip the forearm a little bit tighter than normal and pull the stock back into my shoulder maybe a little firmer thanI would with a heavier rifle. I use Barnes Bullets over Rl15 powder but it seems to shoot other loads and bullets fine. I would suggest continuing to shoot it will drop your group size.
 
.3MOA said:
Any suggestions are welcome.
Click to expand...

@.3MOA , welcome to the forum.

@jmr40 covered the issue of shooting a light rifle and it can't be overstated. Shooting a light rifle is all about recoil management and maintaining consistent form. You can get away with sloppy form with a big, heavy rifle but a light one will show every error.

I bought my gf a Kimber Montana .308 Win a couple of years back. It really likes Hornady 150gr SST factory ammo and I worked up a Barnes TTSX 165gr load for it that was also very good but somewhat temperature sensitive.

Hornady Superperformance 150gr SST

84m_hornady_sp_150gr_sst.jpg

Barnes TTSX 165gr handload

45.5gr_5_shots.jpg
 
Fine looking rifle. I'll just re-echo shooting technique on lighter rifles. When I made the step up from 22s and 223 to 308 I used the "normal" bench rest position and found my groups were awful. I thought it was the rifle for a long time until I came across (probably here) the different techniques needed for lighter rifles. Once I started gripping the fore end tighter and bringing it tight into the shoulder my groups went from 3-4 inches to about an inch.
 

@casefull, @Big Halal:
thanks for the tip on grip and shoulder pressure, I'll try out again using your advice next week.

@MCMXI: great groupings - esp with Barnes TTSX 165 gr hand-load. Do you wait between shots for the barrel to cool off ? If so how long ?
What software do you use for group MOA measurement ?

Thanks.

 
.3MOA said:
Do you wait between shots for the barrel to cool off ? If so how long ?
What software do you use for group MOA measurement ?
Click to expand...

No … I shoot all five shots as fast as I can which typically takes around 2-1/2 minutes since I have to recover from recoil, run the bolt, adjust the rifle and get back on target.

I use OnTarget to measure groups.

http://www.6mmbr.com/ontargetsoftware.html
 
I built a lightweight 308 Model 7 Remington back last winter.The rifle,scope,mount,sling and 5 rounds of ammo weigh in at 7 pounds.I made a very light synthetic stock but when I contoured the barrel,I left a little more iron on it that the usual light rifle will have.This successfully made the rifle more balanced compared to most lightweights,as it made for more weight in the front.Light rifles are hard to shoot good at the bench and can really be tough in field positions,especially offhand.I killed a decent 8 point whitetail with it at 100 yards offhand,so I must have got it a little bit right.Most light rifles are rear heavy because of the super thin barrels,and a rearward balance is not at all good for odd field position shooting.My accuracy goal for the gun was 3 shots into an inch or less at 100 yards and it will do that if I hold onto it right.I found 150 grain Swift Sirocco's to be very accurate and the one I shot a deer with did well as far as dropping the deer very quickly.
 
Kimber CC in .308 here; the more I shoot it, the better it groups (my 100 yd groups are now about identical to MCMXI). My initial groups with this rifle were horrible but I am guessing that both I and the rifle “settled in” - learning curve for sure - relax, take the recoil and do not torque the rifle on the bench. I also shoot the 150 SST in handloads (WW brass and primers, 41.2 grains Varget) - my M70 EW in .308 also likes that load.
 
Last edited:
In addition to the weight, there’s the difference in ergonomics between shooting a target rifle and a hunting rifle that takes some acclamation. Then you have the difference in trigger pull. Oh, and mag length ammo vs being able to adjust seating depth.

Almost as important as managing recoil is managing your expectations.

I go though this every hunting season
 
Thank you all for your input.
@Steve S.: what do you mean by torquing the rifle on the bench ? Putting it in a vise ?
 
I think Steve meant with your hands.

Some stocks bend quite a bit when one applies force on them. The variation of the applied force between each shot, almost inevitable for us mortals, will result in groups opening.

It is one of the reasons why I changed the green plastic stock of my Predator for a Boyd's At-One: my cheek weld was sufficient to bend the rifle as per a fellow shooter's observation when I was at the range. Results of this change are positively impressive for shooting groups, but I would now mind toting that one in the field for a full day of walking; it would definitely require a sling, especially if the bipod is on!

I would be led to believe, because it is pricier, that your Kimber is firmer than was originally my Ruger though. Still, I guess it bends a little more than a heavy laminate stock or a chassis.

Like others have pointed out, a target rifle and a hunting rifle have different qualities. The very positive thing about your situation is you now have to practice with another rifle to master its use. More range time is always better. Cheers!
 
I've used/shot at least three lightweights - Rifles inc 300WM, Kimber Montana 300WSM, Kimber MA 308 - just like the OP's. Lightweight rifles do not have as much mass and they are the opposite end of the "huge and heavy" rifles. It's not that they aren't accurate, but they are made to be carried far to shoot a few. They expose every mistake, like mentioned above. I really would not count out any of the OP's groups yet. Even the Nosler BT's on targets 6-8 only have one shot opening up the group. The barnes has the three or four together, but the dispersion is interesting too, with #3 being low right and #5 being high left - unless scope adjustments were involved.

Just a few thoughts:
Consistent hold and trigger pull are incredibly important. Enlarged groups and flyers can literally be the result of holding it with varying amounts of pressure.
Make sure to get off the bench and shoot from sticks/bipod/slung/ or however you might shoot it in the field.
Barrel heat from longer strings or environment can be a problem. I've seen three shots go in the proverbial one ragged hole and the next two significantly open up the group. Lightweights aren't bench guns (for long) although I acknowledge that some of those groups are impressive. Since this is a hunting rifle for most, you want that first cold barrel shot to be right on.
Bullet choice should depend on the game taken and harmonics play a bigger role in load development since a lightweight barrel has less mass and more whip.
 
How far will you comfortably shoot at an animal and what animal? A whitetail has a vital zone of around 9”, maybe bigger, at 300yds that is a 3moa group or comparable to the 3” sticky targets you where shooting at

Instead of shooting five shot groups after you have an acceptably accurate load, take 2 shots at 2” or 3” target at 100 yds,

If you can hit them 10/10 your gun is perfectly acceptable for hunting

As you shoot the gun, focus on fundamentals, and try to do everything the same from one shot to another, cheek pressure, hand pressure, trigger pressure and follow through, dry fire twice at the target for every live shot taken
 
Good points. The last elk I shot was from a sitting position, about 170 yds. The elk before that was prone at just under 300 yds. Definitely not bench rest steady shots but typical for me, plus heart rate a little elevated.
In both instances I was not concerned about the mechanical accuracy of the Kimber. Lol it was me that was the potential problem.
I like to practice offhand and prone shooting at objects to find out where rifle hits in a more realistic hunting situation.
The Op's rifle has a good stock.
 
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.3MOA, as better stated by Frostbite, I had a tendency to want to put the death grip on my Kimber in anticipation of the much sharper recoil of this light rifle. Once I realized that the recoil wasn’t a life-ending event and the eye relief was not that critical (I was always anxious about a scope in my eye), once I settled down and relaxed a bit, my groups were great - a light rifle learning curve for me. Cooling time is important for these thin barrels (a little heat opens my groups), reloads also gave me much more grouping consistency (eliminated my many fliers). As has been stated, I learned that this Kimber was a first shot, hunting rifle - an absolute joy to carry all day but not intended as a 100 round bench session rifle. I check the zero every deer season - the first shot out of this rifle is usually the best - 1” high dead center at 100 yards. As stated by Nature Boy, my Kimber was not my M70 - I had to manage my expectations.
 
Thank you guys for the valuable info and advice you've dispensed.
I'll update this thread as I make progress (hopefully).
 
Went to range with this rifle 4 more times since last post (I'm at 155 rounds through it), trying to heed advice from you guys:
-> Strong forearm grip without torquing
-> Couple of dry shots before each live one
-> Allowed about 1 minute between shots for barrel to cool off (I know MCMXI doesn't but I need to decouple my mistakes from other unfavorable factors such as barrel temp)
-> Solid lean into rifle
-> Did mostly 3 shot groups (with 2 exception) - I don't necessarily want to test myself for competition, this is for hunting
-> Scope zeroed at 200 yards so at 100 yards impacts will group about 2" above
All from bench (no prone shooting at range I go to), setting rifle on backpack, no sand bags.
Shot mostly 168 gr sierra match king, hornady ELDM 155 gr and hornady superperformance SST 165 gr.
I grouped SMK best, ELDM so-so, I messed up SST (which worked great for MCMXI) - all my bad most likely.

I also measured the ammo CBTO and shot it in groups of like-size.

Best groups I got were from SMK, one 4-shot group from yesterday with 2.1725"-2.1735" CBTO rounds which surprised the hell out of me - probably luck involved
(note I wanted to put a fifth in but I didn't have one left in the same CBTO length category so didn't):

SMK.1.4_GRPH.jpg



Same day first group (one above was 4th group) I got with SMK CBTO 2.1745"-2.1775"
(note that between 1st and 4th groups I was at 1.18, 0.677, 0.796, 0.48 MAX MOA, respectively)
SMK.1.1_GRPH.jpg


Best group I got on previous shooting session (last week) with SMK also, all rounds 2.1715" CBTO:

SMK_GRPH.jpg



And then I got that with ELD superperformance (SST 155) yesterday towards the end of the session:

HNDY.2.2_GRPH.jpg

My next steps are: more practice to get consistency - at least 2 or so 30-round sessions
or perhaps 5+ sessions with fewer rounds because I notice the impact of fatigue on
precision half-way through.

Then I might consider hand-loading.
 
MCMXI said:
@.3MOAthe issue of shooting a light rifle and it can't be overstated. Shooting a light rifle is all about recoil management and maintaining consistent form. You can get away with sloppy form with a big, heavy rifle but a light one will show every error.
Click to expand...

This.

Shooting lightweight rifles when you're used to heavy critters is not unlike transitioning from a full on bagger to a crotch rocket or street fighter, where the movements you made on the big, heavy bike without consequence make a light, nimble machine squirm all over.

I built a 19 ounce .22 pack rifle. It's a joy to carry around, but very difficult to shoot well. Every tiny movement affects POA/POI.

Another thing about very light rifles is that they have very light barrels, which whip/oscillate more than heavier profiles. That doesn't mean they can't be accurate, but it does mean that variations in velocity have a greater impact on POI shift. Ergo, the best way to wring out good accuracy is ammo with the most consistent velocity, which is best done by handloading, but if you don't, there are factory ammo options which get close.
 
@.3MOA, you're getting very good results with that rifle, particularly off a backpack!! Well done on all targets posted. You're clearly well on your way to mastering such a light rifle.
 
Great shooting. Especially considering you're not cheating with a lead sled or similar device. Plenty accurate enough for hunting.
 
Posting only to ask if you're cleaning your bore of guilded metal fouling before you shoot those Barnes pure copper spitzers.

Asking because I understand that the guilded metal (the copper alloy of a jacketed bullet) doesn't play well with the pure copper fouling.

You may see improved accuracy if you can segregate your fouling sessions.

I'm still learning, so for those that must, flame away! :thumbup:
 
@MCMXI, @Casefull, thanks guys, I'm keeping at it !
Just joined a hunting club (I'm in California where it's hard to get to areas with game without owning
land as most public areas are over-hunted, at least for wild boar, and our deer are rather small),
will probably go for a boar hunt soon.



@200Apples I'm learning and will be for the rest of my life.

I always thought I should clean my bore after each round of shooting but lately I've run across people
who seem to know what they're talking about (with apparently verifiable evidence) claiming it makes little
or no difference whether you clean the bore more often than after 500-600 shots. FWIW this guy here (I
may be attaching the wrong episode of his 8-part series):
claims he's been getting good groups throughout the lives of his barrels without cleaning them anymore
often than 600 or so shots so I'm not sure what to think.

Y'all comment.
 
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