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Discussion Starter #1
I have a question about prepping unfired brass for match reloading. I've been reading about how the inside neck thickness can be out of true making the hole in the case essentially off center to the neck which is cured the first time the brass is fired and formed to the chamber.

I'm thinking the best way to prep unfired brass might be to load a minimum charge after uniforming and deburring the primer pocket and full length resizing and trimming to length. Perhaps using a relatively cheap light bullet, for example in .223 using 55 grain vs the 80 grain I might load for 600 yards in a match.

It seems to me that turning the neck **after** fire forming rather than before might give more consistent neck concentricity and thickness than turning the neck before firing.

Does anyone have experience with this? I'd love to hear what y'all have done.

FYI, I'm neck trimming to get more consistent neck tension on the bullet.

Cheers!
 

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Welcome to the forum.

Uneven neck thickness is not cured by firing. That would require a lot more metal flow than happens in a firing event. Normally that problem is cured by outside neck turning or by buying better made, more expensive brass like Lapua or Norma, which doesn't have the problem in the first place (at least, no worse than 0.001" total indicated runout; about twice that to three times that is pretty typical of domestic brass).
 

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Discussion Starter #3
Thanks UncleNick!
Sounds like I'd be better served by buying Lapua brass. Would it be worth do you think for Service Rifle Across-the-Course? I'm just starting out, so perhaps going that route might be more accuracy than I can actually shoot. On the other hand, I would certainly know that my results aren't being skewed by my ammunition. (which came first, the chicken or the egg?)

I plan to develop loads from the bench using a scope and lead sled on my service rifle, then take the scope off and then get down in position with the sling and all.

Cheers!
 

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Sierra Reloading for Semi-Autos and Service Rifles exterior ballistics Sorting brass lots by weight gets rid of flyers. IMO. I run a small test comparing untured to turned. Didnt make a lot of difference. The turned brass sizes easier when the expander pulls thru the necks. I like my bushing dies i use for the 243 win.
Your results may be different. I use the Lyman outside neck turning attachment that fits onto the trimmer. Not the best, but it seems to work ok.
 

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Thanks UncleNick!
Sounds like I'd be better served by buying Lapua brass. Would it be worth do you think for Service Rifle Across-the-Course? I'm just starting out, so perhaps going that route might be more accuracy than I can actually shoot. On the other hand, I would certainly know that my results aren't being skewed by my ammunition. (which came first, the chicken or the egg?)

I plan to develop loads from the bench using a scope and lead sled on my service rifle, then take the scope off and then get down in position with the sling and all.

Cheers!
Some folks have found that to REALLY test your rifle, a lead sled is not in your best interests. I can't say exactly why, but many have speculated that it doesn't allow the rifle to recoil freely. Whatever the case, I have learned that my very best groups will not come with my rifle in a mechanical rest. Heavy bags, front and rear, are the way to go, IMO.

(It's not like a 223 is gonna beat you up, either.)
 

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Can you expand on that? I don't understand the advantage of the bag over the sled. I'm not trying to test the rifle, I'm trying to take out all the human factors in order to see what the load I'm developing really does. I agree about the recoil. I'm not going to flinch from a .223.

I was thinking about this before buying the sled, that perhaps recoil could drive the sled laterally and change the POI of the next shot. My sled will have a 25 lb bag of lead shot in the tray to weight it so I'm thinking that shouldn't be a factor.

I'd love to have suggestions on a heavy bag too... I looked for those first and what I found didn't impress me as being either heavy or stable.

Cheers!
 

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I can't really expand on it, other than to say rifles do not recoil the same way every time, when shot from a lead sled. They can be used to sight in a hunting rifle, and are a Godsend for sighting in slug guns, but for really good shooters, better accuracy is achieved off bags. Maybe that isn't true for every shooter or every rifle, but it has absolutely been my experience.
 

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Bench Rest-The rifle must recoil the same for every shot.

Mechanical rests- The 25 lbs shot should keep it from moving. The forearm is locked in by a vice grip feature on some rests. If you watch the recoil on a few shots, the forearm pops loose on some. One shooter claimed the point of impact changed when removing the rifle from his rest. The units that have no shot weight will slide at times under recoil and other times the rubber feet grip the bench causing the rest to lift. Then there is the cheap light weight plastic front rest that looks like it would work with a sand bag on top. But under recoil , the rest is pulled back and the the bag lifts, causing vertical. Bipods are another story.
 

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Thanks!
My sled has a strap to hold the fore end down to the front support, and a slot rest in the back for the butt-stock to fit into. I have a 25 lb weight bag in the tray. I haven't shot from it yet, but it is designed to accommodate an AR-15 or lever gun. I'll be working up loads for Service Rifle and am a rank beginner at that at the tender age of almost 58.

I'll post my results here for the collective knowledge. If anyone has a heavy bag they've used that they like I'm all ears. The only experience I have shooting from the bench is with the Hornady flip-up style fore end rests which I'm totally unimpressed with.

I did an Appleseed last summer and earned my Rifleman's badge and learned a lot about shooting from position with a sling. It's really different from trap and skeet which is what I've been shooting and reloading for. I love new experiences!

Now all I need is for my upper to come back from Rock River, which should be here on Wednesday. After waiting 6 months for a National Match rifle from them, the front sight was bent when I got it. There was zero padding in their shipping case for the rifle. Couldn't believe it. It's what looks like a nice plastic case but my rifle will never see the inside of that again.

Cheers!
 

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Thanks!
My sled has a strap to hold the fore end down to the front support, and a slot rest in the back for the butt-stock to fit into. I have a 25 lb weight bag in the tray. I haven't shot from it yet, but it is designed to accommodate an AR-15 or lever gun. I'll be working up loads for Service Rifle and am a rank beginner at that at the tender age of almost 58.

I'll post my results here for the collective knowledge. If anyone has a heavy bag they've used that they like I'm all ears. The only experience I have shooting from the bench is with the Hornady flip-up style fore end rests which I'm totally unimpressed with.

I did an Appleseed last summer and earned my Rifleman's badge and learned a lot about shooting from position with a sling. It's really different from trap and skeet which is what I've been shooting and reloading for. I love new experiences!

Now all I need is for my upper to come back from Rock River, which should be here on Wednesday. After waiting 6 months for a National Match rifle from them, the front sight was bent when I got it. There was zero padding in their shipping case for the rifle. Couldn't believe it. It's what looks like a nice plastic case but my rifle will never see the inside of that again.

Cheers!

Don't chuck that RR plastic case. Just get yourself some closed cell foam and cut it to fit the rifle. Then it will keep things from shifting and provide plenty of protection. That's what I did with mine. With proper fitting, you can break it down and have enough room to get an extra upper in there if it doesn't have a scope on it.
 

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FWIW....regarding lead sled vs sandbags...I can confirm other poster's experience that the sled can slide under recoil, fore end can slide around the front rest, etc but on balance I think the sled is a godsend for higher volume load development and sight in purposes. I use moderate to medium recoil calibers (.243, 30-30, 7M-08, 30-06). I justify the sled as a means of minimizing the human factor looking for consistency of groups. For pre-season final sight-in I do revert to sandbags.
 

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That's exactly what I do, as well, Brad. The only difference being that I will also set the sled aside when I really want to see just how good a load can shoot from a given rifle.
 

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Most vertical POI and stringing is initiated by a recoil moment that is due to the bore line of most rifle designs being above the point at which the butt plate is supported by the shooter. This creates a moment because recoil applies torque to that point of contact in proportion to the height of the bore line above that contact point times the recoil force. This lifts the barrel up.

Since recoil force acts equally and oppositely and simultaneously on the rifle and the bullet and powder mass it is pushing forward, the rifle moves back and torques up a little before the bullet clears the muzzle. This is why it affects POI. The equal and opposite momentum that results from the equal and opposite simultaneous force has moved the rifle back by an distance easily estimated. Take the bullet weight plus half the powder charge weight in grains. Divide by 7000 to put the answer in pounds instead of in grains. Divide the resulting pounds by the weight of the rifle in pounds. Multiply the result by the distance the bullet travels in your barrel (barrel length less case length plus seating depth). For Garands and M14's, this is typically around 1/16". For an AR it's less than half that.

One reason the sleds can exaggerate vertical POI shift is the cradle the toe of the stock, which is further from the bore line than your shoulder is in prone. That makes it worse. The best thing is to try to minimize sled influence on POI altogether. Set it up so the gun can move as far as you've calculated before coming hard against the back of the sled sling. A layer of carpet scrap can help.


As to cartridge cases, you'll find that normal cases that are not perfectly symmetrical in the neck can be used to achieve groups as small as half an moa in bolt rifles if they are loaded carefully. The other case prep measures can help, particularly with long range, where the lower velocity standard deviation that results from deburring flash holes and uniforming primer pocket depths can pay of if you are already shooting high master scores. If you are not, then it gets pretty hard to tell the difference.

The Lapua brass comes without flash hole burrs, and with very uniform primer pockets, so you could skip those steps with it. But it costs a lot. I don't know anybody using it in the AR platform for that reason. It's mostly something a benchrest shooter uses. I tend to rely on LC cases for the AR, and I sort the best for matches with a gauge. As to uniforming the primer pockets and the like, a high master class shooter will pick up the extra odd X or scratch ten from following the benchrest practices, so it's something to keep in mind for when you get there.

The reason you can't tell the difference at lower levels has to do with how group error sources add up. Suppose your gun shoots 1 moa off the bench, but you average more like 3 moa at your current skill level. The assumption most shooters would make is that this means the gun contributes 1 moa and they contribute 2 moa, so that a perfect gun would get their groups down to 2 moa. But group diameters caused by different error sources don't add directly like that. For that to be true, both sources of error would have to always be acting on the exact same two shots out of the group that happen to be furthest apart (group size), and to be acting in the same direction away from center for each of those two shots. What are the odds? 1 each, not good. The actual change in group size is an artifact of how the standard deviations caused by the contributing error sources add, and that is as the square root of the sum of the squares of the contributing standard deviations. For circular group error sources, its the same as adding the areas of the groups made by the contributing error sources independently, rather than by adding their diameters.

So, if you have a 3 moa groups from a gun that mechanically can shoot 1 moa, the shooter error is contributing:

√(3²-1²) = √(9-1) = √8 = 2.83 moa of error.

That would be the result if you got that gun to shoot perfectly. Your group size would drop from 3 moa to 2.83 moa. Yeah, you'd pick up more scratch points here and there, but its not like it would take you up to the next classification. And you are not going to get the gun to shoot perfect bugholes anyway. Suppose you could improve the hypothesized 1 moa AR to ½ moa by carefully tweaking loads, just to pick a couple of numbers. That means your groups would come down by:

√(3²-0.5²) = √(9-0.25) = √8.75 = 2.96 moa of error.

The end result is, you'd go to all that extra case prep and precision loading technique just to see 0.04 moa knocked off your 3 moa groups. That's not going to make or break your shooting career. Your scores will benefit way, way, more from using the same money to load a larger number of regular cases reasonably well and to use those to get the extra trigger time and position practice. If you want to get a few Lapua cases to play with and to see what difference you can make with them off the bench, that's a fine hobby, too. Just bear in mind you'll lose a certain amount of brass to the range grass gods at most matches, and losing that expensive brass really hurts. Save it for when you are good enough to have a chance of placing in a major competition.
 

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Discussion Starter #15
Thanks, UncleNick!
I appreciate the detailed post. That's good information. I did order some Lapua brass and I'll post results here when I have some. Got the upper back from RRA yesterday. I plan to load some Hornady cases I already have primed tomorrow and got out Saturday morning.

With luck I won't lose too much brass. Here in Las Vegas we don't have grass at the range. :) It's all gravel. I usually try to get the very end lane so my brass gets thrown out where no one else is going to be.

If I had to guess, I'd say you're an engineer of some kind.

Cheers!
 

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You guessed correctly.

One thing I've done before, when it wasn't too windy, is take a music stand to the range and dangle some Nylon door screen off of it so the brass hit the screen. It tends to absorb the velocity of the brass and cause it to drop more straight down. It's not perfect, but cuts your losses some. A box underneath the screen will catch a lot of them. There are also commercial brass catchers you can get, but most attach to the weapon, which isn't allowed in a service rifle match. So you'd have to decide whether using one bothered your practice any. Magazine changes are where I'd me most concerned to watch out for interference by one.
 

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I'm a week late posting these results, life got busy!

Overall, the test was positive. I was disappointed in the performance of the sled. I had trouble calling the shot because the rifle jumped off target with the recoil despite being firmly strapped down in the sled. I think I'll try the Caldwell Rock Rest and a rear bag. I think that will stay on target better. If anyone has a heavy bag they like I'd love to hear about it. I didn't like the feeling of being disconnected from the rifle even though my shoulder was up against the sled. BTW, I was using a Nikon P223 3x9x40 scope on 3x at 100 yards mounted on the carry handle.

It was a very windy day but I tested against a similar factory match ammo and got more consistent results with my stuff. I loaded once fired (by me as unfired cases) Hornady .223 Rem brass, WSR primers, Varget 21.0 grains (starting load) and SMK 77 gr bullets with a light crimp. Cases had been prepped with FLR, uniformed primer pockets, flash holes deburred, trimmed to 1.750 (I have a Giraud trimmer and love it!) That baby does the trim, deburr, and chamfer all in one step, 10 seconds per case. Pricey but worth every cent.) The factory ammo I used was Fiocchi Match .223 Rem, SMK 77 gr.

Because of the wind I didn't shoot all I had brought. I'll do that in my next range session and hope for a still or light wind day. Right now as I write this the wind is howling outside, must be 50 mph gusts or higher! As tomorrow is Mothers Day, I don't expect to get out to the range until next week.

Thanks to everyone for their help and feedback! It's gratefully appreciated.
 
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