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cdoc42

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I had started a thread on this caliber but it was a while ago, so I thought I'd just start a new one. In 40 years of reloading I've never had this much trouble getting a load under 1 inch, center-to-center. I have a Kimber Model 84 Hunter, 22-inch barrel, advertises a match grade barrel, free-floated, guarantee 1 MOA with factory ammo. So my expectation was I should be able to reload this baby with no problem.

I've worked up 16 different loads with Hornady 140gr SST, Berger 140 VLD, Sierra 140 Game Master and Sierra 120gr GM. The Bergers must be seated to match the magazine, 2.800" which is 0.09" from the lands.The Hornady also must fit the mag and it is 0.08" from the lands. Thus I moved to Sierra because they are shorter and I can get them 0.015" to 0.020" away from the lands and still fit the magazine.

In the 140gr loads I've used H4350, 38.0, 38.5, 39.0 and 40.0gr; Superformance 43.0, 43.5 and 44.0gr


In the 120gr, H4350 43.0gr and Varget 38.0gr

Virtually all loads (3 shots) have 1.75" to 3.75" groups. I got close with Sierra 140gr and Superformance 43.0gr at 0.02". 5 shots measured 1.11" center to center. I recall Unclenick stating if you find an accurate distance it will probably be the same for other bullets in that rifle. I found that to be true with another powder: 38.0gr of H4350 also gave me a 3-shot group 1.11"

Seating the Sierra 140 at 0.015 with Superformance had an incredible change: I had a 3-shot, dead center but vertical string 3.75" long. Increasing the 0.02 seat to 43.5gr and 44.0gr got me 2.5" and 1.75" respectively.

Seating the 140 at 0.015 with H4350 did the same thing. 38.5gr = 2.75" group and 39.0gr= 2 shot at 9/16 and a flyer 2.25" out.

The 120gr with H4350 and Varget gave me groups of 2.25" to 3-9/16" so I won't detail those.

So what's my next step to fine-tune this 140gr Sierra bullet at 0.02"seat depth? Going up in charge didn't work. Should I lower the charge? Should I try to seat toward 0.03"? Should I change powder?

I have a chart of burning rates and I know they are all relative, but useful to compare. There are 149 powders, so I marked them from 1 to 149, fastest to slowest. Varget is 86/149; H4350 is 117/149; Superformance is 129/149.
It's interesting that my best groups were obtained with a burn rate of 117 and 129 - quite a spread.

Two listed in Lyman's 50th Ed that are close to these are IMR4350 (115/149) and Hybrid-V 100 (121/149).
The barrel is free-floated. Should I try to put a small wedge of wood at the end of the stock just to support the barrel at that point? I(If it works, the next step would be to use glas bedding at that point.

Where would you guys go from here?
 
I guess I would ask: Did you do a full ladder test? Starting at the minimum recommended powder charge and going up in 0.7% increments? If not I would do that, as I ALWAYS do that first. I agree with uncle Nick that once you find the best jump, it won't change much bullet to bullet. But the accuracy node may be small and if so, you may be missing it.
But some bullets are more jump sensitive than others. Sierra is typically less jump sensitive in my experience than Berger vld.

Varget, H1000, Benchmark, H4831 &H4831SC, Retumbo, are my go to powders in a big variety of loads/calibers.
 
First, a disclaimer

CAUTION: The following sources include either all unofficial or at best mixed loading data from official, unconfirmed and unofficial sources. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assume any liability for any damage or injury resulting from use of this information.

I use the hornady eld's and have fantastic results. I don't understand why you can't load them further from the lands(deeper seating) and have them fit in the magazine. Also, iirc the hornady book max is 40.9 of h4350, so I'd try bumping up the charge. I've herd people going as high as 43 ish(note:disclaimer). Also try smaller increments. I personally do .3 grain increments, even .2 sometimes. You'd be surprised how narrow a node can be
 
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Have you considered that you may have a bad rifle. I'm not bashing Kimber, I have one in 308 that I like and it shoots well. But ever manufacturer turns out a bad one and Kimber seems to have more than some others.
 
Mississippi, no, I have not done the full ladder test and maybe it is now time for this old dog to learn new tricks. Most often I simply use 0.5gr increments and focus on seating depth. It seems the wall I've run into is caused by my inability to seat the Berger and Hornady bullets closer to the lands because of the magazine size.

nhyrum, I CAN seat them deeper; I have been focusing on getting closer to the lands. Deeper seating requires that I use caution with the powder charge, I suppose, as I'll intrude into the available powder space, esp. with Berger. For that reason, despite several references mentioned H4350 up to 43 or so grains, I've been hesitant. The Lyman 50th edition lists 10 powders for the 140gr bullet but only 4 have a max charge of 40.2-44.0 gr (Superformance being 44.0); all others range from 32.8 to 39.5. How deeply do you seat at times (using the base to ogive measurement)? A Berger site suggests starting at 0.01 and ending at 0.130 with 4 increments.

jmr40, I have considered the rifle as a cause, but I've read, especially with the Model 84 Hunter, Kimber's attention is focused on accuracy as opposed to their past, beauty. I have written to them, however, and their reply is pending.

Since I've gotten the best group with Sierra 140 Game King, I take the advice given here and play with smaller incremental charges.
 
I'd buy a box of factory ammo and see if the 1 MOA with factory ammo guarantee holds. If it doesn't, see if you can't get Kimber to rebarrel the rifle.

The only other suggestion is to try some 123gr A-Max bullets.

Jimro
 
Here is how I do a ladder to find the most accurate load. It saves some time and resources.

Suppose the minimum and maximum recommend powder charge for a given bullet/powder combo is 46-50 grains. What I will usually do is a 1% ladder from the bottom to the top. So in this case I would start at 46 and move up in 0.5 grain increments. Obviously you need to watch for pressure signs as you move up.

Once I have found the upper end of the safe range, I check the group size of each test load. Let's say in my example it is 48.5 grains grouping at about 1". My next step is testing around 48.5 grains. I would start at 48.2 grains and go up to say 48.8 grains to find the exact (or as close to exact as I can get) powder charge giving best accuracy. This procedure can drop that 1" group down to 1/2 somtimes. However, in some guns it will reduce group size more than 1/2 moa depending on sensitivity.

You may also find, referring back to my hypothetical, that 49 is more accurate than 48 grains. In that case I would doy .1 grain ladder beginning closer to 48.5....say 48.4 and go up to 49.

This procedure however assumes you have found the best jump already. If you change the jump afterwards obviously the optimal charge can change.
 
How do you incorporate the jump into the ladder? If the charge range is 46-50 gr, do you start at, e.g., 0.01" jump with that range, and do it all over again at 0.015?

Or do you start at, say 46 gr and make 3 loads at 0.01, 0.015 and 0.02, then move up the ladder with the next charge at all 3 jumps?

Jimro, I'l have to check references to see if Kimber suggests a specific factory load that they use to honor the warranty. Is the A-Max bullet satisfactory for hunting or just target practice?
 
The A-Max is a target bullet only. If you want a hunting bullet in the 123gr range you should try the 120gr GMX.

Jimro
 
CDOC42,

It has been my experience that the most accurate jump will not change with the powder. So to check jump, I just use the "accuracy load" from the manual and check some seating/jump distances. If the accuracy load is near the max, I will usually scale it back a bit. Whichever jump is most accurate with the "accuracy load" is usually the most accurate across the board.

However, the most accurate powder charge WILL change with jump....because the closer you are to the lands, the less gas escapes before the bullet seals the chamber by being forced into the rifiling....AND, changing the seating depth increases/decreases case space and therefore pressure.

So, in a nutshell, settle on seating depth first, then do the powder ladder...otherwise you would literally have to do several ladders.
 
Thanks, jimro and Mspi (I don't feel like spelling it all out) as well as other players. I'll report progress if this post doesn't get lost along the way.
 
I've been eyeing a few different 6.5 Creedmore guns and the Kimber Hunter was definitely in the short list (the .280ai perked my ears too). Please let us know Kimbers reply. Thanks.


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I have had trouble with two 260s I built:
VZ24 Mausers actions Douglas 10" twist barrel. [worked with 100 gr NBT]
Comm Mauser action Shilen match stainless 9" twist.

But a 6.5-06 I built on a Dumoulin Mauser action Shilen select match 8" twist barrel is 5 shots under an inch at 100 yards. [worked with 120 gr NBT, but not heavier long range bullets]
 
Well, the experimenting with the 6.5mm Creedmore is over. Finally.

My best group was 1.111" with 5 shots at 100 yards with 43.0gr of Superformance with a Sierra Gameking .264 BT Spire, seated 0.02" from the lands. So I worked with that. Note I recognize recommendations for accuracy analysis don't include 3 shots, but I figure, on a practical basis, 1-2 should be all I ever need for hunting, so a 3-shot group tells me what I need to know.

Repeat: 3 shots 0.986" with 2 shots measuring 0.236"

Repeat 3 shots 0.3298"

Mississippi mentioned working around a potential load, so I moved 0.3gr on either side of 43.0 gr, just for the hell of it. Amazing difference. 42.7gr gave me a 3.003" group and 43.3gr gave me 1.24" (both 3 shots). That's a new one on me, even after 40 years of reloading.

Also interesting is I then fired 5 shots using only new cases which had been trimmed, champfered and deburred, and primer pockets swaged. The group measured 1.24" center to center. So it might be my initial "foray" may have blocked success on that basis. Once fired, I resize by setting shoulder back 0.003", so it seems this rifle needs cases that closely fit the chamber.

Thanks to everyone. I still have an answer pending from Kimber; I'll report on that for those who expressed an interest.
 
I had (4) Kimbers and the only one I still have and that shoots worth a darn is the .204 84M Varmint.

My .243 Montana made a trip back to the factory for a rebarrel and my 06' and .280 AI also got shipped down the road.

The 06' would shoot around 1 MOA, but the AI would never go under 1" no matter what I did. Ended up putting a brake on the .280 as it was brutal to shoot.

I ended up taking all the money from the ones I sold and built one custom .308 that flat out shoots.

I guess my point is I've been through enough Kimbers now to not want to spend any further money on them... they sure feel and look nice, but I just can't justify the cost for the accuracy I get.


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.
Mississippi mentioned working around a potential load, so I moved 0.3gr on either side of 43.0 gr, just for the hell of it. Amazing difference. 42.7gr gave me a 3.003" group and 43.3gr gave me 1.24" (both 3 shots). That's a new one on me, even after 40 years of reloading.
Click to expand...

Surprising indeed the first time you realize how much less than 1% percentage of the total charge matters and then you find what I like to call the sensitivity of your load to Powder deviation in tenths

The other thing that helps is finding a powder that fills the case.....makes it less sensitive to having a powder gap or powder settlement.... which equals tight standard deviation.

Bryon
 
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