KIMBER MT. ASCENT GOES NUTS

[Stumppuller]

All the Kimber rifles I've owned come from the factory with 4-pound triggers.

Just came into a Mt. Ascent in 280 Ackley. Before adjusting the trigger I took it to the range, and it produced sub-MOA groups at 100-yards.

Disassembled it to adjust the trigger to 2.5 pounds. Called the factory and asked what the proper torque rating was for the guard screws. They said 65-inch/lbs which seems a little HIGH to me.

Torqued the screws to 55-inch/pounds, went to the range and it was spreading the shots out to 3".

The only conclusion I have is the torque rating. Still think 65-inch/lbs is too high. Any experience or recommendations for guard screw torque ratings with a synthetic stock and pillar bedding??

 

[Turnbolt53]

A friend that is an engineer for Kimber told me 65 in-lbs as well.

 

[shinbone]

This thread about my similar experience with a Kimber Montana in 25-06 may be helpful, to you, especially the last page. (unfortunately, there is some internet BS to wade through to get to the nuggets of useful info).

Summary: When I tried to torque the front screw to 65inch/lbs, the front pillar "spun" in the forearm. Who knows how long it had been loose before it became bad enough for me to notice. Plus, the barrel wasn't fully floated. Again, not sure when that problem first cropped up. And, I had a bad scope. And, make sure you have done the Kimber "pre-flight" procedures, especially making sure the mag box does not bind between the action and stock. And, anything less than a 5-shot group is not a reliable indicator of accuracy.

https://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/13673898/1

 

[Rick Richard]

65 in-lbs is what a lot of manufactures suggest for SYNTHETIC stocks. I don't think the torque setting is the problem. I think it may be something binding maybe due to uneven torque procedure. Just my opinion based on my experience.

 

[MagnumManiac]

I use a "T" allen wrench to torque all of my action screws. It twists and stops rotating when the torque is just right.
Being an engine builder, I can tell you that if you are NOT lubricating your screws, your torque readings will be off by as much as 30% and the possibility of breaking one goes up EVERY time they are torqued DRY.
I recommend using nickel anti-seize on ALL threads when torque is critical.
One easy way to know if your torque is on the money is if the screw/bolt 'cracks' when you loosen them.

Cheers.

 

[Turnbolt53]

65 in-lbs is what a lot of manufactures suggest for SYNTHETIC stocks. I don't think the torque setting is the problem. I think it may be something binding maybe due to uneven torque procedure. Just my opinion based on my experience.

Check to make sure that the magazine box is not binding. You should be able to wiggle it a little with your finger through the ejection port.

It's pretty easy to get the mag box in a little skewed during reassembly.

 

[Dry Heat?]

A 5 shot group with a Mountain Ascent is useless. The Soda Straw Barrel heats up too quick, unless you let it cool between shots. I can put 3 Barnes 145 gr LRX Bullets at 2800 fps in my wife's 7mm-08 into a 3/8" group at 100 yards, shooting as fast as I can get good and settled back into the rest. 4th Shot opens it up to 3/4". Didn't bother with a 5th shot as I could see where this was going. The Kimber Mountain Ascent was designed to carry and put that first shot and a follow up shot or two on target, not shoot long strings of shots. Don't waste time trying 5 shot groups, unless of course you let the Barrel cool between shots. And get a Wheeler torque driver, set it at 65 inch pounds and torque those puppies down in the proper sequence

 

[Dean2]

5x3 shot groups, fired on the same target is every bit as good an indicator of accuracy as 3x5 shot groups and with the pencil thin barrels, it is actually a far better indicator. Don't care how good a barrel or build too much heat in a real thin barrel is going to move POI. There is a reason bench guns have 1" barrels on them.

I would use the recommended torgue, as said do not torque dry and I would be using some Prussian blue on the action to make sure I had even contact with the bedding. Would also check the pillars for loose or high spots. Other thing to look at is the bottom metal, does it sit flush and square, Prussian blue helps with this too. Anything that binds or is not completely in line and flush can affect how the gun shoots.

 

[skipglo]

All the Kimber rifles I've owned come from the factory with 4-pound triggers.

Just came into a Mt. Ascent in 280 Ackley. Before adjusting the trigger I took it to the range, and it produced sub-MOA groups at 100-yards.

Disassembled it to adjust the trigger to 2.5 pounds. Called the factory and asked what the proper torque rating was for the guard screws. They said 65-inch/lbs which seems a little HIGH to me.

Torqued the screws to 55-inch/pounds, went to the range and it was spreading the shots out to 3".

The only conclusion I have is the torque rating. Still think 65-inch/lbs is too high. Any experience or recommendations for guard screw torque ratings with a synthetic stock and pillar bedding??

I believe I would trust the manufacturer

 

[Reloder28]

Weatherby torque spec's are 55 in/lb's. Don't reckon Kimber's requirement is too far fetched. If anybody knows, the manufacturer should.

 

[shinbone]

A person can shoot however many shots they want when checking for accuracy and call it good. It all depends on the person's goal.

When checking a rifle or load for hunting accuracy, 3 shots can be good enough because that is probably more than will be shot when the gun is used in the field. With just 3 shots, however, a 3/4" group one day can easily be a 1-1/2" group the next. That is still "minute of deer," and still good enough for hunting, but that is hardly a reliable measure of the gun's/load's true accuracy.

When measuring a gun and/or load for accuracy, 5 shot groups are needed to reduce the group-to-group variation so the gun's/load's true accuracy becomes apparent. There will still be group-to-group variation with 5-shot groups, but it will be much smaller than with 3-shot groups. Of course, more than 5 shots will be even better, but there is a point of diminishing returns, and 5-shots is the generally recognized standard for such measurements.

JMHO

 

[lancetkenyon]

I ALWAYS check torque of action screws when disassembling a rifle. That way, I can put it back exactly the way it came apart.

Some torque testing is now in order to redetermine the sweet spot. Take them down to 25 in/lbs and hit the range with a torque wrench. Shoot a group. Retorque up in 5 in/lbs increments front first, then rear, and try again. Find the best torque and record it. I have had great results doing this if 55-65 in/lbs doesn't work. Sometimes, front and rear at minor different torque setting work best.

 

[freddiej]

Oh GOOD GOD! Kimber is yanking chains here. 65 inch/pounds is only for fully aluminum bedded synthetic stocks. pillar bedded stocks work best by a feel method. I will explain. First. I am a pistolmith, I own a small shop in North Western Nevada. I have four pillar bedded stocks and 2 full aluminum bedded stocks. 65 inch/pounds are on my fully aluminum bedded stocks, the pillar bedded stocks I set the front screw to 35 inch/pounds plus or minus 10 inch/pounds (what ever the gun likes most) and the rear just snug it with an allen screw driver. if this combo works then it works. what you need to do is mess around with 1 to 5 inch/pound increments to see what your gun likes. if this does not work.. glas-bed your stock immediately and then just give the front screw a good moderate to hard snug, then the rear just snug it up. it's now up to you to take or leave my advice. BTW I have a Kimber Montana in 270 WSM that shoots sub-1/2 inch groups.

 

[Dean2]

A person can shoot however many shots they want when checking for accuracy and call it good. It all depends on the person's goal.

When checking a rifle or load for hunting accuracy, 3 shots can be good enough because that is probably more than will be shot when the gun is used in the field. With just 3 shots, however, a 3/4" group one day can easily be a 1-1/2" group the next. That is still "minute of deer," and still good enough for hunting, but that is hardly a reliable measure of the gun's/load's true accuracy.

When measuring a gun and/or load for accuracy, 5 shot groups are needed to reduce the group-to-group variation so the gun's/load's true accuracy becomes apparent. There will still be group-to-group variation with 5-shot groups, but it will be much smaller than with 3-shot groups. Of course, more than 5 shots will be even better, but there is a point of diminishing returns, and 5-shots is the generally recognized standard for such measurements.

JMHO

Thee idea that groups with larger numbers of shots improves the accuracy of results is the result of statistical measurement issues. It also assumes that the variables affecting the 5th shot are exactly the same as what affected the first shot. With thin barrels and heat build up we know this is patently NOT true, and realistically it isn't even true in heavier barrels unless the rate of fire is slow enough to ensure adequate cooling to ambient for each shot.

Let us not confuse statistical analysis with real world results obtained when shooting groups and not letting the barrel cool fully between every shot. Just because a 5 shot group is the accepted norm does not make it the right answer in every situation. If you can shoot 5 3 shot groups in a row that are under .5 and you can do that three days in a row then you really do have a 1/2 minute gun and load. Shooting 5 shot groups won't make this more true.