Gentlemen,
I am not new to reloading, but have a some of unanswered questions that I would truly like help to answer.

I am working up .308 win loads for a Kimber Longmaster.
I have used Stony Point tools to determine the ogive on every bullet that I wanted to use. I have found that beyond a doubt that this rifle will shoot .5moa at 100 yds using 168bthp Hornaday using many charge wts of RL 15. The distance off the lands that this rifle prefers for the 168bthp Hornaday is .010 inches. Unfortunately this COAL is way to long to fit in the magazine. If I start backing off the lands, a linear regression in accuracy occurs.
I am now in the process of trying to work up a hunting load for elk and deer using Barnes 168 gr TSX bullets. Again the same problem with COAL .
Barnes recommends starting .050 off the lands. Even at this distance the COAL is too long to fit in the Kimber mag. The max COAL that will fit in the Kimber mag is 2.826. This COAL will put the ogive .071 off the lands. I have not shot any of these loads yet, but have my doubts that they will perform to my liking.
Is this issue with cartridge length vs. distance from the lands common?
I have the same issue with my 22-250 77V Ruger. Fortunately it doesn’t care too much how far the bullet ogive is off from the lands. It shoots just about anything well.
I know a lot of you will say "man. How good of accuracy do you need for hunting?" I am a good shot and it is just a personal thing to get sub MOA out of any load that I use for any of my rifles.
Is this a common problem?

Thanks
Dave Hyde

Yes it is a common problem with factory rifles. These rifles have long throats. Long throats reduce the risk of pressure problems, which reduce lawsuit risks. At least that is my theory.

If you want a short throated rifle, call a gunsmith and get a barrel installed and talk about what you want.

I have shot thousands of 168 Hornady Match 168's and found them relatively jump insensitive, but my accuracy criteria is based on cleaning highpower rifle targets.

This is going to sound very rude, but your accuracy criteria is unrealistic. Take your 0.5 MOA rifle and shoot it unsupported and see what group sizes you get. I have no doubt that your rifle will not be the greatest source of inaccuracy in the system.

Kinda have the same issue with my pre64 m70 308 with long tip bullets like Balistic tips.

Hornaday 165 sp's and Lapua mega 185gr I can load close to the lands and still fit the mag. Nosler patitions should work.

SlamFire,
I don't think for a minute that your comment was rude, just factual.
I agree that I am the greatest variation is the system. I have fired this rifle without rests (sitting)and the best I have ever got was groups about about 3 inches on my best day, Prone is a little better, but not much.
I like to shoot bench rest and maybe I should get a custom like you suggest.
But it would be nice if my hunting rifle would satify both wants.
Thanks.
I agree with you about the lawsuit stuff.

Thanks
Dave Hyde

GSP7,

Thanks for the tip, I will give them a try.

Dave Hyde

Hey Dave,

Welcome to the world of factory rifle! Thank the Lawyers!

Anyway, you have a cfew options.

1. Shorten up your rounds so that they can cycle thru your magazine then work up new loads using this new seating depth.

2. Place a single shot follower in the action and shoot it as a single shot. Able to keep current COAL. However, if this is going to be a field gun, I would come off the lands more than 0.10". This is OK for a bench gun but doesn't fare well in the field.

3. Have your barrel taken off and rechambered to a short throat 308. My recommendation is a 308 Obermeyer, it has an 0.085" leade. You have a choice between either the original chambering or one with a tight neck (0.333"), but using the later will require neck turning. I have the latter one in my Hunter Benchrest rifle and it works very well.

4. Have a new barrel chambered up as above. But doing this you have the option of changing the barrel twist based on the bullet you will shoot the most. A good all-around for the 308 is a 1-12".

5. Make sure you know what type (length of bullets) you plan to shoot and have your rifle set up so the bullet's base is not seated past the neck shoulder junction if at all possible. This way you do not loose case capacity. Optimum is to have this set up and still be able to cycle thru the magazine.

Hope this helps.

Mike

quote:

Originally posted by SlamFire:
This is going to sound very rude, but your accuracy criteria is unrealistic. Take your 0.5 MOA rifle and shoot it unsupported and see what group sizes you get. I have no doubt that your rifle will not be the greatest source of inaccuracy in the system.

thats why you have to have the rifle shooting its best. if hes doing 3" groups from sitting and its doing 0.5" from a bench, then surely a 1" group off the bench will mean a 6" group from a sitting position?

In the field i think shooting off a day pack is ideal, as long as you have something like a rain jacket in there you'll be fine. IMO, if you have a rest like that, youll have more chance of hitting something at 300 yards than from a standing, unsupported shot at 100 yards.


MSwickard, explain why have a load that is 10 thou off the lands and using it for a hunting load out in the field is a bad idea, as id like to hear your reasoning, and if its a good reason or something you have learnt from experience maybe everyone should hear it.

Old Swedes and Weatherbys have long throats, and I have never heard of them not preforming well. Try the longest COL that fits your magazine and play with the jump from there. You may just be suprised.
Switch to a Speer, Nosler or Sierra SP bullet and you`ll likely hit the leade before the COL is too much for your rifle. The ogives of different bullets mean some seat deep and others shallow to ride at the same distance from the lands. Don`t try to limit your bullet choice and you should find something that works for you.

“thats why you have to have the rifle shooting its best. if hes doing 3" groups from sitting and its doing 0.5" from a bench, then surely a 1" group off the bench will mean a 6" group from a sitting position?â€


Hey Paul: I used the word unsupported without much explanation, would have taken away from the “punchiness†of the statement. Maybe I should have just left it as “off the benchâ€.

I have a number of lightweight hunting rifles, and I have a bunch of heavy match rifles. If I could, I would be shooting in a Highpower rifle match every weekend. Offhand is very hard to do, and really it is truly “unsupportedâ€. In 100 yard matches I have put 10 shots offhand into the ten ring. (About 3 3/8†circle) But it is so rare I keep the targets to brag about. The other positions, sitting and prone, we use a sling. A military three loop sling is a tremendous aid to accurate shooting. But seldom have I ever been able to take the time to sling into position in hunting situations. The best I have done is shoot with a hasty sling, which is still better than nothing.

One day after a local 100 yard Highpower match, which I shot an outstanding score, I wanted to shoot my J.C. Higgins M50 rifle in 30-06. http://www.gunsandammomag.com/classics/ct0407/ This rifle with the ammo I was shooting is capable of 1.25†at 100 yards on the bench. Now I had placed most of my 20 shots prone with an iron sighted match rifle within an inch at 100 yards. That day I shot my M50 sitting with a hasty sling. Basically I could barely keep with in four inches at 100 yards with the thing. These lightweight hunting rifles are hard to shoot accurately off the bench. And I really doubt that making that rifle a .5 MOA beasty would have reduced the group size. More practice with the thing would have helped.

I recently read an article where Jeff Cooper was quoted as saying a scout rifle only needed to be 3.5 MOA. Well, maybe so.

ok i understand what your saying now.
but surely if the rifle is shooting a more accurate load it must make some difference for when it comes time to shoot free hand (even though it might be minor).

and you would be dead right about the practice part, i never even thought about it.

Probably, undoubtably. But I do not know how to model the system. Someone with a statistics back ground could probably tell me what the system average would be when you have a (lets say) 2 MOA shooter with a 1 MOA rifle. Or a 1 MOA shooter with a 1 MOA rifle. Assuming a normal distribution for each.

Back before my brain calcified, I might have been able to do that. Not any more.

Paul from NZ

quote:

MSwickard, explain why have a load that is 10 thou off the lands and using it for a hunting load out in the field is a bad idea, as id like to hear your reasoning, and if its a good reason or something you have learnt from experience maybe everyone should hear it.

The biggest factor is pressure! Most individuals really can't say how close they are to the rifling successfully. Myself included and I shoot competitive BR. However, I know I'm in the ballpark.

Getting the bullet too close to the rifling can also cause some nightmares in the field. For one a bullet can stick in the rifling and when you go to remove the cartridge the bullet stays in the throat and you have an action full of powder. Another, is grit etc can work itself into the action and stick a bullet, plus elevate pressures because the bullet can't make the jump to the lands.

Bottomline, we are not talking about BR accuracy here. If a rifle can shoot 1-1.5" # 100 or even sub 1" with bullets jumping to the lands (say 0.50-0.070) it is still sub Critter moa. Best to use OAL's recommended in the various Bibles. This allows for unwanted pressure spikes and allows the cartridges to feed well thru the magazine.

Gentlemen,

Thank you all for the advice and comments.
I think that I learned that having a hunting rifle using bullets very close to the lands could be risky, especially when you fall in the mud a lot like me.
I am going to work up loads .050-.070 from the lands, try for best accuracy out of this Kimber and accept the best I can do.
I think I will be looking for a BR rifle to satisfy my craving for target accuracy.

Dave Hyde