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Old April 21, 2013, 08:43 AM   #26
buckhorn_cortez
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Quote:
There's a few myths floating around in this thread. Especially this one.....

Quote:
With a bolt gun, if you're very careful on overall cartridge length (case stretch at the neck), you can neck resize only for 3-4 uses. By doing that, you're using fire-formed cases and you're accuracy will improve very slightly because the case is fitted to the chamber.
Maybe you'd like to explain why. Cases stretch. Depending upon the type of case, they stretch in different places. 45-70's stretch at the base (web) and you will finally get a crack at the web after reloading the brass a number of times.

338 brass stretches over the entire length of the cartridge. I would guess because the round is held in the chamber by the belt. 6mm seems to stretch (in my rifle) mostly at the neck.

The point being - the brass gets longer as you shoot it so if you reload it and crimp at the same point (top of the neck) without trimming the case, the overall length of the round is longer as the brass is reloaded a number of times. At some point, it will not cycle reliably in a semi-auto even though it still fits in the magazine - at least not in my semi-autos when I've tried repeated neck resizing instead of full length resizing.

As for fire forming - I can only relate my experience. Two of my rifles exhibit slightly better accuracy with neck resized ammunition than with full length resized ammunition when shot from a sled comparing the same load. The accuracy improvement is very small - but repeatable with my rifles.

The last thing I will say on accuracy is that I have also found that the concentricity of the round has a great effect on accuracy. I chased an accuracy problem for nearly 3 months with my .308 AR using factory ammunition. When I started measuring every round for concentricty I found the factory ammunition to vary as much as 0.009 between rounds.

I started sorting the rounds into groups by how close to zero they measured. I then loaded 5 rounds of 0.001 - 0.003 and tested the rifle with two 5 shot groups. The average of the two groups at 100 yards was .428. When I took the remaining rounds and randomly loaded them in 5 shot batches - the main grouping opened up to nearly 0.75 inches not including a flyer in each group that would have opened the groups up to nearly 1.25 inches.

I don't do "myths" or repeat "myths" - I go by my experience which, granted, is emperical testing and may not be repeatable by anyone else - but, that's the only information I can relate is my experience with a subject.
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Old April 21, 2013, 08:51 AM   #27
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I think that a good bolt action and a good semi auto are more accurate than the Person that shoots them. So the action type is Personal preference. There are advantages and disadvantages to every action type.
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Old April 21, 2013, 10:32 AM   #28
Bart B.
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velocette says:
Quote:
There must be a reason that the AR is essentially the only rifle on the line at high power matches.
They are the only ones used in high power service rifle matches. That's required by the rules for the most part.

But in high power match rifle matches, bolt actions shoot the best scores and accuracy test groups. Those such as the Tubb 2000 or others of that type shoot the best scores through 600 yards when rapid fire is required in some stages of the matches and they're a lot easier to build and be accurate when new. Bolt action rifles with more conventional stocks are still producing the best scores in high power any rifle mid and long range matches from 600 to 1000 yards where single shot actions can be used. And the AR10's in 7.62 NATO are now finally as accurrate as the old M1 and M14 rifles were and still are. None of the semiauto's have done as well against the bolt guns; too many parts to get back into the exact same position for each shot; a bolt gun's only got one - the bolt.

The most accurate semiautos shoot inside 4 inches at 600 yards. They've been doing that for decades. Bolt guns of equal quality stay under 3 inches at 600; they've been doing that since the 1960's But the modern "tube" or AR designs for both bolt action repeaters and semiauto versions are easier to shoot more accurate as the recoil's more in line with the point of butt contact with the shooter's shoulder; the rifle moves less while the bullet goes down the barrel.

buckhorn says:
Quote:
There are a couple of other things with an auto versus bolt gun. If you reload, you'll have to full length resize the cases to get them to feed properly in an auto. With a bolt gun, if you're very careful on overall cartridge length (case stretch at the neck), you can neck resize only for 3-4 uses. By doing that, you're using fire-formed cases and you're accuracy will improve very slightly because the case is fitted to the chamber.
Best accuracy with most of the semiautos' been done with either commercial match ammo or handloads with new cases. Few, if any 'smiths square up the bolt face in an AR platform. This lets the first firing of a new case have its head forced out of sqare and no resizing process straightens it up.

Full length sizing fired cases from the bolt guns has produced best accuracy for decades. Some folks get a few dozen reloads per case if the right tools are used correctly. Virtually all of the benchresters moved to full length sizing a few years ago, their smallest groups stayed the same size but their largest ones got smaller. A brand new rimless bottleneck case has its neck and bullet perfectly centered in the chamber throat when fired, just like full length and neck only sized ones. But full length sizing fired bottleneck cases puts their neck better centered on their shoulder; the body's held in place while the neck's sized back down to hold the bullet.
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Last edited by Bart B.; April 21, 2013 at 10:44 AM.
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Old April 21, 2013, 11:21 AM   #29
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Speedy bolt action:
http://www.youtube.com/watch?v=uwnc3b2GW40
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Old April 21, 2013, 01:25 PM   #30
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I have been intrigued with these
http://www.savagearms.com/firearms/m...TROPHYHUNTERXP
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Old April 21, 2013, 01:34 PM   #31
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Quote:
Speedy bolt action:
http://www.youtube.com/watch?v=uwnc3b2GW40
You think that's a speedy bolt action? Checkout this shooter with a similar rifle.
http://www.youtube.com/watch?v=iiajg...kNmuu1rTKLX-pA
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Old April 21, 2013, 07:45 PM   #32
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It's been known for decades that the more lugs there are on a bolt, the better it will shoot ammo. . .but only with new cases whose head's ain't perfectly square. This is why George Swenson designed his 4-lug Swing action back in 1972 for the Brits to use shooting arsenal ammo (poor case head squareness, but otherwise very accurate in good lots) in their rifle matches. No handloads nor commercial ammo was/is allowed. Everyone had to shoot the same ammo. It "levels the playing field" according to the Brit's reasoning.

But there's no accuracy degradation of a 2-lug actions when their bolt face is squared up with the chamber axis. They shoot reloads as good as can be had. Although the best of those 2-lug M1 and M14 rebuilt semiauto match rifles would shoot good lots of Federal match ammo inside about 4 inches at 600.

I don't know of any AR or any other semiauto platform that shoots inside 3 inches at 600 yards with any ammo. There are BR (bolt rifle) ones that'll do that with the best handloads.
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Old April 24, 2013, 08:27 AM   #33
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Quote:
I don't know of any AR or any other semiauto platform that shoots inside 3 inches at 600 yards with any ammo.
How about 5" at 1000?

http://www.youtube.com/watch?v=UxGmusWYATE
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Old April 24, 2013, 08:36 AM   #34
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Bart B,

I really enjoy your posts. A lot of thought goes into them. Thanks!
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Old April 24, 2013, 11:11 PM   #35
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I'm not gonna say one is more accurate then the other. It's all about the shooter anyway.

OP was asking about long range, I've shot serveral 1000 yard matches, My best score ever was my M1A Super Match using irons.

Is it more accurate then my (target) bolt guns??? I don't think so. But I was shooting for the guard at the time and shot the crap out of my M1A.

Meaning a whole bunch more trigger time. After a while, without looking for figuring, you can check the mirage and adjust he sights with out even really thinking about it.

If I sent as many rounds down range with one of my bolt guns, I'm sure I could shoot it as good.

As too ARs in Competition. The Cheapest way to get into high power is to go the AR route. Its easier to shoot so you have more ladies and juniors in the game now days.

The CMP doesn't have a Match Rifle citatory. Pretty much everything is service rifle. That means AR, M1A/M14, M1. A match quality gun in an AR platform is the cheapest way to go.

Yeah the NRA allows match rifles, but as one gets involved in High Power, they start looking and working for their Distinguished Rifle Badge.

That program is run by the CMP, and again, that means service rifle. Seems to me it makes sense to shoot high power with the same setup you need or the Dist. Rifle Matches.

I remember many people got into the NRA Master Class or High Master with their bolt guns and aperture sights, but had a hell of a time getting the distinguished points away from Sharpshooters and Experts who used Service Rifles across the course.

My idea of the perfect gun, between Semi and Bolt guns is to have several of each.
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Old April 25, 2013, 11:21 AM   #36
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My DPMS LR308-AP4 (16 inch barrel) fitted with a 2-10 Nightforce scope will shoot my hand loaded ammunition in 2.0 inches at 300 meters. (.75 MOA) (average of five, five shot groups.)

This, of course is from a solid rest.

I load the 168 grain Sierra matchking in Federal Match cases. Black Hills match ammo will duplicate my own loads in my rifle.
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Old April 25, 2013, 05:04 PM   #37
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Alabama, that's a good video. But only 5 shots.

I've put 5 consecutive shots with aperture sights inside 5 inches at 1000 yards twice, but no way would I ever claim either of those Palma rifles were that accurate. Both were more realistically .75 MOA dingers at that range but the smallest 15-shot group on paper shooting off my shoulder I've shot is about 1.7 MOA. Just like all those long range benchrest rifles holding records; 3/4 MOA systems that, once in a great while, put 5 shots into about 1 inch and everybody screams joyously that such accuracy was attained as it sets a new record. Then his next 5-shot groups about 6 inches and he and his stuff never ever shoots another one-incher for the life of the barrel. Such is the laws of statistics and averages.

For all readers,

Note the US Army Marksmanship Unit finally gave up getting their 5.56 NATO chambered match grade semiauto service rifles on AR type platforms to shoot as well in the 1000 yard matches at the Nationals as folks using 7.62 Garands or M1A's. The 7.62 round had been producing better scores than any 5.56 NATO chambered mouse gun for a long time. They didn't have any more good M14NM's that would have done as well; that program shut down a long time ago.

So the US Army was able to convince the NRA to change the rules for what constitutes a "service rifle" and now an AR10 is legal in long range NRA matches They rebuilt some AR10's and shot Berger 185 VLD's in really hot loads (tossed the cases, not safe for reloading) and set a Service Rifle Team record at 1000 yards at last year's Nationals. But their scores were still not quite as good as the bolt guns shooting the same cartridge at long range.

Regarding the accuracy level one needs for long range accuracy, the more accurate your rifle will shoot good ammo, the better you'll score; targets or game. Shoulder fired rifles end up adding at least 1 MOA to the accuracy inheirant to the rifle and ammo. Nobody holds them perfectly still nor exactly the same for each shot.
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Old April 25, 2013, 05:26 PM   #38
Bart B.
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Ben Dover says his DPMS LR308-AP4 (16 inch barrel) fitted with a 2-10 Nightforce scope will shoot my hand loaded ammunition in 2.0 inches at 300 meters. (.75 MOA) (average of five, five shot groups.).

Sounds very realistic to me.

What's the size of the largest groups, Ben? I estimate them to be about 3 inches (one MOA) or more.
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Old April 25, 2013, 08:04 PM   #39
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Quote:
the US Army was able to convince the NRA to change the rules for what constitutes a "service rifle" and now an AR10 is legal in long range NRA matches
Problem is, the CMP doesn't recognize the AR10 in it's matches. So NRA guys start whining cause they can't shoot their rifles in EIC matches or other CMP games.

I have to side with the CMP on this, and the spirit of the game.

The end goal for most high power shooters is the Distinguished Rifle Badge. I recommend any going after the DRB stick to the CMP Rules in choosing a rifle.

There may be more accurate rifles, but they do you no good in chasing points.

Although if you get something like a White Oak, you can shoot some dern good scores.
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Old April 25, 2013, 09:42 PM   #40
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That is a good point Bart. The power of advertising overwhelmed me.

The AR-10 was never a standard issue rifle for the US military. It is embarrassing the way they are throwing it out there now for competition.
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Old April 26, 2013, 04:19 AM   #41
Bart B.
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Kraig's comment:
Quote:
Problem is, the CMP doesn't recognize the AR10 in it's matches. So NRA guys start whining cause they can't shoot their rifles in EIC matches or other CMP games.
Good point. Here's another that effects folks wanting to shoot Palma matches or even get on the US Palma Team.

The other issue is for those shooting high power rifle matches using Their 30 caliber Garands. No problem shooting NRA and CMP matches with it. But it's no longer allowed in Palma matches. Back in about 1990, I wrote the first rule for the NRA High Power Rifle Rule Book stating any rifle in .308 Win./7.62 NATO or .30-06 could be used. The reason was so folks who only had an original Garand, M1903 or M1917 .30-06 could still use it in Palma matches shot in the USA. That got struck some years ago by the NRA High Power Committee and now says the rifle used in Palma matches has to be chambered for the .308/7.62 mm NATO or .223/5.56 mm NATO cartridge case. Folks who used to be able to use their 30 caliber Garands can no longer do so. Only those Garand owners whose barrel has a 7.62 NATO chamber can.
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Old April 26, 2013, 08:21 AM   #42
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Big problem is your not comparing apples to apples. If you look at the "Palma Rifle" it's a custom down to the reamer used so it's not a 308 the average shooter would use. Even the Tubbs rifle it carry's a 5K price tag.

http://www.6mmbr.com/palmabasics.html

This is picture of firing line at Palma Match

http://riflemansjournal.blogspot.com...for-palma.html

Bart is right bolt action is accurate but you buy it and that's the name of the game.
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Old April 26, 2013, 05:50 PM   #43
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As far as I know, all the reamers used on the US Palma Team's rifles are pretty much standard SAAMI spec ones except the leade will be a bit short so the Sierra 155's will be pushed into the lands a bit when the round's chambered. That the only critical chamber point for the ammo.

The rest of the chamber does not have to be a perfect fit to the case except for having a 1.630" headspace (or whatever allows about .002" of head clearance for issued ammo). All the ammo (new cases or full length sized ones) will center perfectly up front in the chamber anyway.
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Old April 26, 2013, 07:44 PM   #44
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Well here is one Palma reamer.

http://www.longrangehunting.com/arti...products-1.php

Here is some other ones

http://benchrest.com/archive/index.php/t-66956.html?
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Old April 26, 2013, 08:23 PM   #45
Bart B.
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Long Range Hunting's link has a good picture but it's to coarse to see what the chamber dimensions actually are. Excellent info on more recent Palma reamers.

The benchrest.com article's a good one for info.

Note the chamber neck diameters. There's lots of clearance on ammo with .3084" diameter Sierra Palma bullets and the .3445" chamber neck. Ammo neck diameters' typically been in the .337" to .338" range; .003" or more clearance around the neck of a loaded round. Chambers are not "tight necked."
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Old April 28, 2013, 09:48 AM   #46
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Bart, my groups at 300 will run from anout 1.5 smallest, to 3.0 largest.

I consider the inherent accuracy of the rifle/scope/shooter to be well defined in the average of five each, five shot groups.

Of course, this is not a bench rest test.
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Old April 29, 2013, 12:06 PM   #47
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Ben says the inherent accuracy of the rifle/scope/shooter to be well defined in the average of five each, five shot groups.

OK. Then how does one decide which of two shooting systems is the most accurate when one's set of five 5-shot groups ranges from 3 to 5 inches and the other's group sizes go from well under 1 to over 8 inches when the average group size of both systems is 4 inches?
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Old May 7, 2013, 04:17 AM   #48
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Back to what the OP asked....it boils down to money. But not on the rifle. An accurate bolt gun - and with computer controlled machines factory rifles now are very good- is still cheaper than an accurate semi auto usually. This means the shooter has more cash to spend on optics....a pretty vital consideration if you ask me. That extra grand on optics can get rather important way out yonder.

From a degree of experience you can get a semi auto to shoot rather well. The most accurate I have ever fired is a PSG1 which is nice, but very pricey. A friend of mine shoots very well with a RRA in .308, which is tremendous. Personally, I prefer bolt actions....but to each is own. If you like what you have, you will shoot better with it.
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Old May 7, 2013, 01:12 PM   #49
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A good bolt action will cost MUCH less than a good semi.
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Old May 7, 2013, 02:53 PM   #50
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A good bolt action will cost MUCH less than a good semi.
No doubt. I don't think anyone can name a centerfire semi-auto that'll shoot MOA (or exceptionally close) from the factory, with factory ammo for less than $600-700. If there is I'd love to know about it. I'd probably jump on it in a heartbeat, if it was proven to have that accuracy and feed with reasonable reliability.
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