My nephew got a 30-06 Kimber Mountain Assent as a graduation present. As we started to develop loads for it, we settled upon the Hornady 178 grain bullet and IMR4350 powder, 56.5 grains. After several sessions of shooting we were very surprised, not only by it's accuracy, but also the velocities we were getting from the 24" barreled light rifle. Groups around .7 and velocities right at 3,000 fps, were proven out after 9 or so shooting sessions. I guess we are going to call this rifle a junior 300 H&H.

Good Shooting

Jerry

3k for a bullet of that weight would seem exceptionally fast or high pressure

180's typically top out just over 2800 and/or we'll below 2900

Id be pretty concerned over that as velocity at 2750 to 2800 FPS is "plus max" in any 30-06..but the 30-06 pressure test loads are about 180,000 PSI, so your getting away with it or your chronograph is on the zilch and that's my suspicion because:

My load is 57 grs of the same powder and that's a grain more than yours and it is in my Kimber 84, also a 30-06!! and I get 2733 FPS average for 10 shots taking out the high and low, and that's with a 180 gr. Hornady, Nosler or whatever. It is a max load in my gun..

Check your chronograph, maybe bad lighting, bad shade or whatever..

Well I gotta tell ya. 57 grains of IMR 4350 is the load I use in OTHER 30-06's with 180 grain bullets, and I get right at 2800fps also. This is a real interesting critter, so we started some investigation. The boys dad who was an exhibitor at the NRA show last week and struck up a conversation with a fellow who makes custom test barrels. The 4 questions the barrel maker asked were, do you have any bolt face signature on the head of the case, no: do you have any primers flat or cratered, no: do you have any case head expansion, no: are the cases stretching, no. He said "my guess is you have one of those exceptional barrels, and went on to explain what that was. I won't go into it here as it is a little lengthy. While we were scratching our heads, we went on to eliminate chronograph difficulties. We did these tests over a lot of sessions so we were pretty sure of our numbers. We use an Oehler P35 as our primary chronograph, we also have a Pact Model 1. We shot over both of them, and also in tandem. 3000 fps. Although at times the Pact was maybe 20 fps faster than the Oheler. In my experience 200fps between rifle barrels is not just a possibility it's just about written in stone. But I found this interesting, and figured you might also.

Jerry

I'm not sure what surprises me more

A Kimber that shoots under 2" or the 3k

Ted: This is my 1st experience with a Kimber Rifle, although we have several pistols, and they shoot great. Maybe the guy at the NRA show was right, an exceptional barrel. Don't know!

Jerry

quote:

Originally posted by ted thorn:
I'm not sure what surprises me more

A Kimber that shoots under 2" or the 3k

I would go with the 2"...I have a number of them in the safe that wont do that with their favorite load on my best day on the bench. I've had bad luck with most Kimbers..a real shame because I really like their line-up.

I was REALLY tempted to buy an Assent...but I already have a First Gen Remington titanium that shoot around .5 moa so I just can't take another chance on Kimber.

Have you 2"ers carefully checked out your rifles ?
My 223 was not what it should be ,seems sometimes their QC man was asleep !
Two major things - I could pass a dollar bill between barrel and forend but a light , therefor whippy barrel needs more room .I put a shim under the front of the receiver ,raising the barrel .That cut the groups in half !!
Second problem - mine has a blind magazine which was too long.Cut down the mag so it just touched with screws tight . Now I get my .5 " groups .
No I don't work as a gunsmith but I did learn a few things in CST .

I've done literally everything there can be done to Kimber 84's for myself, friends and family

Re-crowned
Re-floated
Re-bedded
Full bedded
Tip pressure
Mag box clearance
Polish firing pin
Replace firing pin spring
Re-set firing pin protrusion

I'm might think of a couple more things but IMO they build a very nice rifle with way above fit an aesthetics but fail to use a good barrel.....and they bed to a max tolerance slave and not the individual action.

They have poor QC and possibly the worst CS in the firearms industry

quote:

Originally posted by Atkinson:
Id be pretty concerned over that as velocity at 2750 to 2800 FPS is "plus max" in any 30-06..but the 30-06 pressure test loads are about 180,000 PSI, so your getting away with it or your chronograph is on the zilch and that's my suspicion because:

My load is 57 grs of the same powder and that's a grain more than yours and it is in my Kimber 84, also a 30-06!! and I get 2733 FPS average for 10 shots taking out the high and low, and that's with a 180 gr. Hornady, Nosler or whatever. It is a max load in my gun..

Check your chronograph, maybe bad lighting, bad shade or whatever..

I agree. I'd bet good money it won't go over 2800 fps on my chronograph. Better check the batteries, when the battery gets weak, they seem to read way high. Sounds like the accuracy is there however.

quote:

Originally posted by ted thorn:
I've done literally everything there can be done to Kimber 84's for myself, friends and family

Re-crowned
Re-floated
Re-bedded
Full bedded
Tip pressure
Mag box clearance
Polish firing pin
Replace firing pin spring
Re-set firing pin protrusion

I'm might think of a couple more things but IMO they build a very nice rifle with way above fit an aesthetics but fail to use a good barrel.....and they bed to a max tolerance slave and not the individual action.

They have poor QC and possibly the worst CS in the firearms industry

I've done a few of these things as well and sent no less than 3 Kimbers back to the factory. Everything from a warped barrel channel causing pressure on the barrel...so severe nothing but a new stock would fix it..to a firing pin that was so off center it wouldn't strike the primer. It literally hit the case rim. I suspect the chamber was cut crooked as well exaggerating the issue because that one came back with a new barrel and bolt.

The 3rd one wouldn't chamber a round..couldn't even get close to closing the bolt. If you find a Kimber thats a shooter then you are a lucky man IMO..like I said I really like their line-up. I probably would buy nothing but Kimber if they could build with any consistency

Maybe I'm lucky to have gotten a " good "one !

Jerry, This is just one man's opinion. And I think the world of Ken Waters writings and the case head expansion method.

But a number of more recent articles over the last couple decades argued (even demonstrated) how pressures can be way over spec, yet otherwise seem OK. Essentially, the argument is "there are no free ballistic lunches".

I really hated reading that cuz I had one particular rifle go way over specified velocities with manual.....even multiple manual-safe loads. And no pressure signs. This was a 24" 77R in .300 Win that gave 3300 fps with 180s using sub-max book charges of IMR 4831. Felt like 3300 fps, too.

But I now incorporate chronograph results in confirming a load is gtg in a particular rifle.

J Stevens: You did read my post where we used an Oehler P35 as our primary chronograph, backed up by a Pact Model 1. Even used them in tandem!! No batteries are not in this equation. If any of you live in Arizona, perhaps we can shoot over 3 different chronographs, maybe that'll confirm our results. I will tell you all though, empirical statements about shooting are not worth a hill of beans. As to velocities, we own 2, 700Bdl Varmint rifles in 223, exactly the same rifles, shoot the same loads and one is 200fps faster??? Samuel, I have had the same experience as you, with an AR 15 DCM barrel from DPMS. When it was all said and done, 1.5 grains below the minimum suggested load, produced the velocity that was expected with the max load?

Jerry

Jerry

I have 3 Kimbers, and love all three. The latest, a .338 Fed thinks it's a match rifle, the .308 nearly as good and is a consistant 5/8" 3 shot group gun. The .260 took some work, but will shoot sierra 120's into an inch. I would love more of them ..... but don't dare unless I could shoot it first as no way my luck can hold out!

I will add two more things I have done to Kimbers through the years.

Replaced the front action screw (lug screw) on a Montana as the factory supplied screw only engaged one thread. Kimber replaced the screw with the exact same length....nice....no

I replaced it with a Remington screw and ground it to length for a perfect just under the barrel length

I have also opened up the clearance holes on an 84M Classic because of miss alignment

My Kimber shoots a great after I sent it back to the factory and they replaced the defective barrel.

The velocity alone is a sign of high pressure.

So, are the readings pretty consistent when you change the load in that rifle. If you change components do you get expected results or do you get surprising results.

100 FPS is not normal between barrels but I have seen it go that much on rare occasions, thus fast barrels and slow barrels, never have I known of one that would vary 200 FPS, nor have I heard of one...I don't doubt your post, but I feel it needs more investigation as to why? as it would surely concern me, it sounds great, but too good to be true IMO..My next question is how many time can you reload a case before the primers get loose? Its interesting to say the least, and peeks my curiosity?

Here's a picture of a group the load is listed, as is the velocity. Group Measured a little over .700. This is very typical of how this rifle shoots. Most groups are sub 1" the rest will throw a flyer an inch or so out. Ray we are on the 4th loading, and the primer pockets are still tight. Jerry

Is it for sale????? I've given up on Kimbers. I would love to have a Mountain Ascent but don't like to volunteer for grief.

LJS, I doubt it's for sale. It was a graduation present for my nephew getting his BA from Arizona State. According to all the other guys who have responded to this thread, they either had bad luck with the accuracy of Kimber's, or they had a problem believing the velocities we were getting. So far none of this has been a problem. My nephew killed a Buffalo, (bison) in Kansas this march, shot a huge mule deer buck last season in Southern Arizona, and killed a hog or 2 in Texas this April, all with the Hornady bullet.

Jerry

A friend of mine bought a Mountain Ascent a few months ago, and we had great results with it as well. It was shooting 5 shot groups at 3/4" at 100 and 1.5" at 200 with factory Nosler 180 Accubonds. If I didn't already have a Remington 700 Titanium in 30-06 I would definitely go buy a Mountain Ascent without any hesitation.

Jerry: I was just kidding but I may have to give one a try. I understand it will be available in 6.5 Creedmoor. Congratulations to your nephew on his graduation and putting his present to good use.

Yes, I'd love an Adirondack in 7mm-08 or 6.5 Creedmoor, but don't want to gamble on getting a good one.

I had tweeked successfully my 223 Kimber but hadn't gotten it properly christened until today .Grabbed some ammo [I had written 69 BTHP on the plastic box] .Took out a chuck Then I looked at the headstamp --.223 BTHP Lapua Match.I had never written the Lapua Match part on the box .

quote:

Originally posted by Atkinson:
100 FPS is not normal between barrels but I have seen it go that much on rare occasions, thus fast barrels and slow barrels, never have I known of one that would vary 200 FPS, nor have I heard of one...I don't doubt your post, but I feel it needs more investigation as to why? as it would surely concern me, it sounds great, but too good to be true IMO..My next question is how many time can you reload a case before the primers get loose? Its interesting to say the least, and peeks my curiosity?

Absolutely agree Mark. I've loaded my BDL in 270 Win and have been using a load for 4 decades 150g partition at 3000 fps out of a 22" barrel. That's 100 fps faster than most reloading manuals (even the old ones that were not as conservative as today's). 10 reloads per case, then I throw them out. No flattened primers, no hard extraction, no extractor marks on the case head or case head expansion. Some barrels are faster than others, and if you find the right bullet/powder/primer mix you can sometimes attain better velocity and accuracy. 3000 fps does sound awful fast even to me for a 178g bullet out of a 30-06, but pressure might be fine.

I've shot 30-06s all my life, and 2990 with a 178 grain bullet is too HOT, or your chronograph is bonkers. I believe the accuracy.

Double check the velocity with another chronograph, and if it's correct, I'd back off the powder until you're below 2900 fps.

If your chronograph is reading too high, maybe it's set up improperly, or if not and it's that inaccurate, I'd get a new chronograph.

If you can afford it, I'd get the new LabRadar - they are spectacular and worth the price, but you'll have to wait a bit to get one. There's a long line.

90 fps less will not change the outcome of the hunt, but over pressure and a stuck case could change the hunt outcome.

I get my highest velocities when I twist my chrony a bit. I do so when I want to feel better about an accurate load which is a little on the slow side! LOL

One of you guys posted something that's stuck with me for a long time: "the best way to ruin an accurate pet load is to chronograph it"

Zeke

quote:

Originally posted by Ackley Improved User:
I've shot 30-06s all my life, and 2990 with a 178 grain bullet is too HOT, or your chronograph is bonkers. I believe the accuracy.

Double check the velocity with another chronograph, and if it's correct, I'd back off the powder until you're below 2900 fps.

If your chronograph is reading too high, maybe it's set up improperly, or if not and it's that inaccurate, I'd get a new chronograph.

If you can afford it, I'd get the new LabRadar - they are spectacular and worth the price, but you'll have to wait a bit to get one. There's a long line.

90 fps less will not change the outcome of the hunt, but over pressure and a stuck case could change the hunt outcome.

I don't see why anymore testing or load development is needed. Two different good chronographs and high pressure signs are not there. Sounds like a really fast barrel. They exist, and this seems to be one. Might be interesting to try a couple different lot #s of the same powder. Or some different powders altogether to see if the fast barrel theory holds up there as well. However, I'd just go hunting.

That fast 30/06 sounds like a smooth, tight barrel to me...and maybe a generous throat(?)

I'd like to know what the internal land/groove dimensions are of that barrel.

Interesting all right.

Colorado Matt: Thanks for reading my posts before commenting about chronographs. If an Oehler P-35 in tandem with a Pact Model 1 doesn't do the job, well! Also, I posted about 2, 700BDL varmint rifles in 223, where the same load is 200fps faster in one than the other. That's my experience ,I have learned nothing is written in stone, regardless of what's in print.

Jerry

Jerry,
I've had similar experiences, and don't doubt your results. I have a Kimber in 8400 in 300 Win Mag which also has a particularly fast barrel.

I shoot over an Oehler 35P as well, and have absolute confidence in this chrony. In fact I have two of them, and have on occasion set them up in tandem and been amazed at the consistency of the readings shot to shot.

Several years ago I wrote about buying 4 Winchester 70 featherweights in 30.06. One for each son, my wife and I. Those four, nearly identical factory rifles had a spread of 200 fps from the fastest to the slowest. Three were clustered within 75 fps, but one had a particularly slow barrel.

Usually it is people who don't have much experience shooting over quality chronographs that don't understand this variation. Each barrel is different, some particularly fast or slow, but most of course just average. You just have to do the test to find out what you have.

While not all Kimbers shoot well, I have 4 that are exceptionally accurate, including a Mountain Ascent in 280 AI. It doesn't matter what brand of rifle you buy, some will shoot and others won't. Maybe not the way I want it to be, but that is life.

Bill

The point is not that different barrels will produce different velocities with the same load - this is well known and accepted.

The point is how much pressure is required to achieve 3000 fps with a 178 gr bullet with a 30-06 using IMR4350 and having a 24" barrel.

See QL calculations below, which predicts it would take over 70,000 PSI (at least 10,000 PSI over SAMMI max) for the 30-06 set-up this way to reach 3000 fps MV - to be exact 73,459 PSI.

When you load over 70,000 PSI - although you may get away with it - you are running significant risk of a blown primer and/or stuck case. Excursions happen, and they are hard to predict, but they are much more likely when you load hot.

If you want to hot-rod the '06, I suggest using Re17, MRP, WXR, or Re22. With these powders one can modestly exceed 2900 fps and remain at or slightly below 65,000 PSI.

Cartridge : .30-06 Spring. (SAAMI)
Bullet : .308, 178, Hornady BTHP Match 30631
Useable Case Capaci: 59.320 grain H2O = 3.852 cm³
Cartridge O.A.L. L6: 3.340 inch = 84.84 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : IMR 4350

Predicted data by increasing and decreasing the given charge, incremented in steps of 1.0% of nominal charge.

CAUTION: Figures exceed maximum and minimum recommended loads !

%Fill, Charge, Velocity, Energy, Pmax, Pmuz, Prop.Burnt, Barrel_Time

%Fill, Grains, fps, ft.lbs, psi, psi, %, ms

100 52.20 2656 2788 48449 9006 96.9 1.265
101 52.78 2685 2849 50137 9094 97.3 1.245
102 53.36 2714 2911 51887 9179 97.6 1.226 ! Near Maximum !
103 53.94 2743 2973 53705 9260 98.0 1.208 ! Near Maximum !
104 54.52 2772 3036 55590 9337 98.3 1.190 ! Near Maximum !
105 55.10 2800 3100 57547 9411 98.5 1.172 ! Near Maximum !
106 55.68 2829 3164 59579 9480 98.8 1.154 !DANGEROUS LOAD-DO NOT USE!
107 56.26 2858 3228 61687 9545 99.0 1.137 !DANGEROUS LOAD-DO NOT USE!
109 56.84 2887 3293 63879 9606 99.2 1.120 !DANGEROUS LOAD-DO NOT USE!
110 57.42 2915 3359 66147 9663 99.4 1.103 !DANGEROUS LOAD-DO NOT USE!
111 58.00 2944 3425 68494 9715 99.6 1.087 !DANGEROUS LOAD-DO NOT USE!
112 58.58 2972 3492 70929 9762 99.7 1.071 !DANGEROUS LOAD-DO NOT USE!
113 59.16 3001 3559 73459 9805 99.8 1.055 !DANGEROUS LOAD-DO NOT USE!
114 59.74 3029 3626 76088 9844 99.9 1.039 !DANGEROUS LOAD-DO NOT USE!
115 60.32 3057 3694 78822 9877 100.0 1.024 !DANGEROUS LOAD-DO NOT USE!
116 60.90 3085 3762 81665 9905 100.0 1.009 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 111 58.00 3059 3698 82093 9319 100.0 1.013 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 111 58.00 2778 3050 55554 9680 95.3 1.185 ! Near Maximum !

I think perhaps the best way to determine if this a fast barrel is to clock some factory ammo. It is possible to have really high pressure without the traditional sign of high pressure (but unlikely).

I assure you there is no pressure signs at all. No bolt click, no flat primers no case growth, and no web expansion. I think we'll just keep the loads where they are and enjoy the small groups.

You guys with all that velocity are going to give ole Jeffe a bad case of vocal diarrhea if your not careful. HE has convulsions if one works up a max load in a rifle, hell his 300 Mags only get 2500 FPS with a 110 gr. load..

quote:

Originally posted by Jerry Eden:
I assure you there is no pressure signs at all. No bolt click, no flat primers no case growth, and no web expansion. I think we'll just keep the loads where they are and enjoy the small groups.

Shoot it over a different chrono....

He already did that I'm pretty sure.