Are larger caliber rifles naturally less accurate?

[pondskipper]

So here's my question, I have a 5r milspec 223, a custom built 6xc built on a remington short action with a 28" 1:8 twist broughton barrel in an xlr chassis, and a custom built 338 lapua with a 28" broughton 1:9.3 twist rate barrel mounted to a badger m2013 action in a krg chassis. To date the first two shoot lights out at 100 and 200 yards simply printing groups load testing have done surprisingly well, the 223 even shoots factory hornady 75gr match ammo extremely well and I'm in the process of trying to duplicate the results with that ammo with reloads. Both the 223 and 6xc shoot less than 1/4 moa at 100 yards and are both usually still less than 1/2" at 200 but for the life of me I can't get my 338 to do anything better than I could if I were throwing bricks. I have checked the torque on everything, scope mounts, rings, action to chassis, and I can't get it to shoot anything better than 2" at 200 yards. I've tried 3 different bullets. 300gr Berger, 300gr smk and 285gr amax, and only h1000 for powder in lapua cases with cci mag primers, I have tried charge weights ranging from 87-92 grains and have gone up one in one grain increments, have only loaded them to my maximum mag length so I can still use the magazine, case prep involved simply cleaning up the case necks, chamfering, and one would think that by now I should have seen much better results. The gun was smithed by Dixie precision and they have a great reputation for producing rifles that are more than capable so therefore I'm lost. Could anyone shine some light on this for me please? I just don't understand why i can't get it to do any better when I know it should unless I'm expecting too much accuracy wise from a caliber of its size.

 

[geo4061]

No doubt they will shoot. Look at the pics on this sight. Go take a look at the Defensive Edge 338 that is presently for sale on this sight. It shoots .25. Did Dixie shoot it? How did it shoot for them?

 

[pods8]

Looking for an optimal charge weight (not just 1gr incriments) and then checking seating depth has always worked for me, esp. if a couple bullets were tried. No experience that that particular caliber but I'd step back and do a better refinement on your powder charge determination as a first step, may be jumping right over a nice node.

Also are your shooting fundamentals holding up with the larger caliber?

 

[Pdvdh]

This question would be better posed in the Gunsmithing Forum, because I think seasoned gunsmiths will be in the best position to provide and explain answers.

Given equal quality rifle components, parts, and pieces, I believe that larger caliber rifles shooting heavy bullets at high speeds are less forgiving guns that rifles that shoot smaller caliber and lighter weight bullets. I say this because the large caliber rifle must digest substantially greater forces than the small caliber rifle, even though the cartridges may operate at equal pressure. The larger caliber bores generate more force than the smaller caliber bores, at equal operating pressures.

I believe rifles shooting heavy, large caliber bullets have to be built 'more' properly, to tighter tolerances of fit and alignment, both with regards to metal work, and the bedding in their stocks, in order to shoot well, compared to the smaller caliber rifles.

But I think gunsmiths and competitive shooters would be best positioned to offer answers and opinions. And I'm neither a gunsmith nor a competitive shooter.

 

[longrangehunterII]

Pondskipper,

A lot of variables are at work with any firearm as I'm sure you are well aware of. The 338 LM is a proven round for accuracy in a properly built rifle but has a lot of recoil, even for the seasoned Big Bore shooter. It could be just that simple, or the load isn't tuned to the gun, or the barrel isn't fully broken in, and lastly the gun itself but without further work developing a accurate load or attempting to you'll need to give it some more time IMO.

You've done what I first like doing is finding a bullet the gun likes, but you'll need to test with more then just one powder, RL-33, Retumbo work well in the Lapua Magnum, as well as seating depth.

The recoil from these guns is usually the biggest issue most anyone will have to deal with, and why most people can shoot the lighter recoiling guns much better. That's something I myself was faced with because it left me with a lot of neck pain from shooting prone, due in part to a snowmobile whiplash issue over a year ago. I decide it wasn't worth the trouble, but in reality these guns produce a lot of recoil, even suppressed or with a good brake in a 16 lbs. rifle.

Give it some more testing, and then see what it will produce? Were those 200 yard groups from a bench and a Bench rest or shot prone off a bipod?

***** This was already being written before Phorwath posted his comment which is a lot like what I already wrote.

 

[dragman]

Large calibers can be just as accurate as anything. The things that make it seem that way in a lot of cases is this:
Setup - any good stock with tight screws are plenty stable enough to take small calibers then you tune it in usually pretty easy to get things together. When talking BIG stuff you need to have an action that is heavy and strong enough and the barrel that will give you the harmonics you need too. not to mention that the recoil being much greater the action must be mated to the stock with more surface area and take greater care so that the transfer of recoil is consistent. (Why if you have any LA Remington does EVERY gunsmith recommend a 1 piece steel base) because it stiffens the action helping keep harmonics consistent across temps and conditions.
Given the proper heavy action (CUSTOM) a good barrel heavy enough to deal with big bullets being pushed (I prefer something in at least a medium palma) and it being professionally bedded into a good stock a big gun will shoot side by side with a small gun.

Unless the recoil is too much for the shooter! there are just a lot of stuff to go into shooting bigger guns.

 

[pondskipper]

Well as for fundamentals of shooting the gun are concerned I'm sure that's not the issue, not that I don't or wouldn't want to admit that it was shooter error but because I've shot much lighter magnum rifles that kick much much harder than my 338 does, in all honesty about twice as much, a re barreled 300rum sendero with the original retained factory contour with no muzzle brake that belongs to a friend of mine shooting 208 grain amax and it will definitely bite you on your eyebrow if you aren't careful, and I'm able to keep that nasty thing under control at 200 shooting under 3/4" with it. I always shoot from a bipod, always have and always will, I make sure to try and exert as little force on the gun as necessary to make the shot, I always load the bipod with each shot, keeping my body directly inline with the bore of the rifle to absorb the recoil impulse correctly, with my off hand under the butt stock using a rice filled sock to steady the gun, my lop and cheek weld are always set perfectly, I can completely close my eyes, lay there for a few seconds, re open them and my sight picture never changes and I never need to re adjust. As far as the action and barrel are concerned, they are very much so super heavy duty, the action is a badger ordnance m2013 and the barrel is a no7 contour I think, broughton that has a 4"long 1.250" shank after the action mind you that has a straight taper leading down to 1" at the end of 28" with a badger ordnance fte brake on it. The whole gun weighs about 20 pounds plus the break so it's more than pleasant to shoot honestly.

 

[BountyHunter]

I will disagree with some of the posters that say larger calibers are just as accurate for several reasons. I believe it is totally unrealistic to think a 338 is going to shoot with a tuned 223 or 6XC. If it was true we would see them at all the matches; but we don't for very good reasons.

1. Much more time and effort has been spent on higher quality match grade bullets for smaller calibers. Not much work has been done in the 338 arena for example until a few years ago. There are still issues with higher quality brass for example in the big case arena and lots are spotty from one to the other.

2. Smaller calibers are inherently easier to shoot accurately from a bench versus larger boomers. Big boomers have big recoil normally and muzzle blast and it will effect most people more than they are willing to admit.

Just a simple fact, that no one shoots SR BR with a 338 and very, very few at LR. I only know of one person shooting a 338 successfully in LR and he had a special run of bullets made for him by a big mftr. After that run of bullets was done, so was his run.

However, in your case, I would do more reloading work. Try F215 primers, MRP and MRP2 if H1000 is not working. I and many others have had excellent luck with all three of those powders in multiple 338s. Forget max COAL and try a seating depth experiment to find out where the gun likes them. Start at MAX and work back in big jumps to .120 off from MAX. Go to a rest instead of a bipod for load development work. The bipod just adds another degree of variance to the process.
Hint Hint, sort the bullets by base to ogive. 388 bullets are noted for wide variances especially SMKs.

 

[wbm]

Are larger caliber rifles naturally less accurate?

No.

 

[pondskipper]

I've thought about using retumbo and us869 but figured that out of the 3 brands I tried I figured I would be able to find a bullet it legitimately liked over the rest, stick with that bullet and move to different powders at varying charge weights to further develop loads from there but it's shown no preference to anything at all yet, the last ones I can try is lapua and cutting edge, my intention was to systematically change one thing at a time to help develop loads for it and understand what it was doing and what it liked better.

 

[FearNoWind]

When I have these kinds of problems I simply tear the rifle down, go back to basics and rebuild it from the bottom up. Check all mechanical connection points, clear the barrel channel to provide a LOT of clearance for the barrel, carefully bed the action, torque in proper sequence and correct torque specs.
Then I will often shoot a box of factory rounds so I have a base line to start from. Then I work with a series of loads that vary .1 - .2 grains, ten rounds of each.
Got to keep in mind that comparing the accuracy potention of a .223 to a .308 is like apples and oranges. The smaller caliber can do incredible things at the not so long ranges but it'll fall apart when you try to reach out with it.
I'm a bit curious about the bullet weights you're using to do load development. I might lighten up just a bit and see how a 250 grain performs. Try the 250 grain Sierra MK HPBT.
To the question as to whether larger caliber rifles are naturally less accurate, here's whay my .284 can do:

 

[pondskipper]

I came close to building a straight 284 Winchester, it's bore to case volume is almost identical to the 6xc so barrel life should be in the 2500-3000 round range, the 7mm bullets for their weight compared to a 30 cal of the same weight have an extraordinarily high bc and can be driven pretty darn quick from a 28" tube even using weights in the 180 grain range, though my 6xc will do the same as yours group wise it still suffers a fair amount as range increases with wind but that's to be expected with the lower bc. It seems as though the 30cal range is the true cutoff for truly match grade quality stuff in general. But I can say with absolute confidence that even with my factory 223, coke cans aren't safe at 600 yds as long as the wind settles down.

 

[Cuz]

Seating at mag length, how far off of the lands are you?

 

[pondskipper]

give me just a minute and I'll check.