Vertical stringing.....????

TReX300

TReX300

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A friend of mine that has just gotten into reloading gave me a call yesterday saying he's haveing problems with accuracy using his reloads in .22-250. His gun shoots groups about 1/2" wide and 2-3" tall at 100yrds. With factory ammo and my reloads it will shoot under 3/4" all day. This is his first batch of reloads. He's loading a 50grn Nosler BT on top of 36 grns of Varget. Each powder charge was hand weighed. The OAL length is within .001". Everything seems right. The only thing he didnt do was resize the new Winchester brass he used. I dont know how much that would have to do with it but it is something I do my self. I was wondering if he possibly has the bullet seating die adjusted down to far and is getting a partial crimp. What do you think? I havent seen his set up yet so I haven't been able to go over it. I'm just looing for things to check before I head over there tomorrow.

Thanks
Tim
 
Can be several causes. The most common is action/barrel shift because of heating/bedding shift at recoil, etc. Less common is inconsistant load pressure/velocity. Less common also could be changing rest location on forearm or shooter error. There's something to be said for shooting at 50 yards when load testing- it eliminates some of the other variables. I've found that fairly large amounts of vertical stringing is usually the barrel/action bedding thing, particularly if the barrel touches the forearm. The difference was so obvious after tinkering with that, that there is little doubt that any variable forearm pressure on the barrel will/can cause stringing or other accuracy problems.
 
Well - This appears to be a common topic recently - new reloaders assume that any handload will beat a factory load - particularly if the handload was meticulously prepared.
I'm going to take a different tack with the above post, as the rifle has demonstrated performance with factory loads. I would suspect that the rifle is out of "tune" with that load - ie the barrel is resonating in a vertical plane.
He needs to change the barrel residence time of the bullet - change the bullet weight as a first resort (and possibly the powder speed to match) If he wants to retain the bullet, switch powder.
 
Part of the problem may be that he used new brass and did not re-size it. Now that it is fire-formed to the chamber--partial full length re-size the cases or nech size--check for uniform length--trim if necessary and champfer case mouths--and try the load again. make sure primers are properly seated. Vertical stringing may also be caused by inconsistant ignition.

As said above when you handload you have to work up a load that the individual rifle performs best with--what works in one may not work in another.

44Bore
 
Vertical stringing isn't usually a handloading problem.
My guess is that he is shooting a lot more with the handloads, and seeing the results as the barrel heats.
IMO the number one cause is bedding/stock screws.
That is the barrel, in contact with the stock, as it heats is being pushed upwards.
Loose screws can allow the action to shift, so be sure they are tight first.
Free floating is the easy to check.
Can you slide a piece of paper all the way down the barrel between it and the stock? If not you have contact, and it may be the problem.
Some rifles are designed to have a small contact point, it doesn't always work out.
If that's the problem, you have two choices, either bed the barrel, or free float it.
Free float is the easiest, and if it doesn't work you can always bed it.
 
Put me down for the questionable ammunition theory. Vertical stringing at shorter ranges is more about velocity and consistent ignition. Did the group start at the middle and fluctuate up and down or did the impacts steadily rise or decline? If the gun is shooting well with factory rounds, well with your handloads and the shooter is using the same rest and technique for all shooting, the only variable left giving him trouble is his ammo (assuming atmospheric conditions were similar). I question his decision to NOT (re)size the new brass as that is a fundemental step in (re)loading. Not only the case to chamber relationship is going to be funky but the neck tension on the bullets will all be different. The firing pin isn't going to hit all the primers at the same spot and with the same force either.
That being said, obviously check whatever you can at home on the gun itself before going to the range and check whatever loaded rounds your friend has that weren't fired (if any) for loose bullets and protruding primers.

This is a good read: http://www.rifleman.org.uk/Fuller_group_diagnosis.htm
 
TReX300 said:
His gun shoots groups about 1/2" wide and 2-3" tall at 100yrds. With factory ammo and my reloads it will shoot under 3/4" all day.

Thanks
Tim
Click to expand...

If you are convinced that nothing has changed with his setup between the time you shot it and he did, and if he shot 3/4 inch with your reloads or factory, then it is hard to see how it can be anything else but the reloads. The rifle shoots 3/4 moa at 100 with different loads. That narrows it down to a few things he can try. One thing I did wonder is whether the factory ammo and your reloads have a different bullet, powder, primer, case, etc from his? He might try duplicating your load to see if he gets the same results as you.

What follows is a ramble so be warned (There are a lot of guys that know this, though they might differ with some details):

Whenever I have seen vertical stringing during testing I have 'assumed' it is the load, and this has usually proven to be true in one way or another, especially in rifles that shoot accurately with other loads. But the first thing I do is check all screws (scope, action, etc.) and I pay attention to how the rifle locks up as I tighten the action screws, which tells me a bit about the bedding too. It's easy to do and it builds confidence. To continue, I almost always test a number of loads with a particular powder, e.g. start from minimum or moderate load in a rifle with a fairly large case and work up to max in 0.3 grain steps. I don't shoot a large number of shots at each load level the first time, just enough to give me preliminary information about where I should do most of my testing. (I usually shoot 3 shots at each level, sometimes only two. But don't tell anybody and its Mystic Player's fault when I only shoot two.:p) With a case of low capacity I might work up in 0.2 grain steps. This allows me to see whether there are any anomalies with one particular load, e.g. do I get vertical dispersion with all of the loads, and whether one load is most accurate (Usually two or three are similar across all the loads and it takes more testing to see differences at these 'nodes' if any. It's surprising, how much this kind of testing can tell you.) If the powder is right, and you have an accurate rifle, and if you can shoot reasonably well from a bench, then you will often see the group rotate as the vibration pattern in the barrel changes and you will see the group increase and decrease in size too. So, if your friend is learning to reload I would get him to copy your load and test to see if he can find a slightly more accurate one using the same components and staying within safe parameters. When he is successful at duplicating you, then he could move on with confidence. Much better than a shot in the dark...:D Just my $0.02...fred
 
When you develop loads, you shots will pattern (high, low, left, right..whatever) of you point of aim, and you strive to make the group really really wee. Stringing is a barrel / forearm contact thing. What a few minutes for the barrel to cool between shots
 
Thanks for the replies guys but I dont beleive it is a rifle issue. He can shot one group with my loads or factory ammo thats 3/4" then wait 5 min. and shoot a 1/2" by 3" group with his reloads, wait mintues then go through the whole thing again with the same results. The bullets he's shooting are the same bullets the factory loads are loaded with and loaded at the same velocity going by the book data. Our chronograph is dinked so we cant check for sure. I'll get him to try some full length sized with the same data and see how they shoot.

Thanks
Tim
 
Doesn't sound like the shooter or the rifle then. I guess it's always possible that you wouldn't shoot a vertical string yourself but... You can get some rough idea of relative velocity by looking at how high reloads shot at 100 m and how high factory did. Watching stuff like that kind of gives me a feel for what is going on in a rough sort of way. Measuring web expansion with a micrometer is something I do when comparing to factory too (I forget who first wrote about doing that. Lost in the mists of time ;)). If he isn't close to max with his reload he might try adding and subtracting some powder to see if the group changes with a slightly different vibration pattern in the barrel. It would be a new one on me if full length sizing made a difference. Wouldn't be the first time I have seen something new though. Now that I think about it I have never compared velocities on full-length and neck sized cases with everything else equivalent. Jeez, just for the heck of it I'm going to try that some day.
 
BCFred said:
Doesn't sound like the shooter or the rifle then. I guess it's always possible that you wouldn't shoot a vertical string yourself but... You can get some rough idea of relative velocity by looking at how high reloads shot at 100 m and how high factory did. Watching stuff like that kind of gives me a feel for what is going on in a rough sort of way. Measuring web expansion with a micrometer is something I do when comparing to factory too (I forget who first wrote about doing that. Lost in the mists of time ;)). If he isn't close to max with his reload he might try adding and subtracting some powder to see if the group changes with a slightly different vibration pattern in the barrel. It would be a new one on me if full length sizing made a difference. Wouldn't be the first time I have seen something new though. Now that I think about it I have never compared velocities on full-length and neck sized cases with everything else equivalent. Jeez, just for the heck of it I'm going to try that some day.
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You have some good points, Fred. Sure would be new to me, too, if full length resizing made a difference. When I first started reading this thread I considered it an open and shut case, rifle needs to be bedded. In my mind it seems impossible for the ammunition to be the cause of vertical stringing.
Everytime I see on some thread where someones rifle "likes" 57.2 grains of shootrite powder, but goes all over the place with 57.4 grains of it, I see a rifle that needs bedding.
I know, there are a lot of people on here, including some of the most reliable and respected shooters on these threads, that say they tune their ammunition to their riflle. I certainly respect and listen to their views.
It just happens that my opinion differs. I think a well tuned rifle will shoot any good ammunition well, unless there is something basically wrong with the rifle. All of my bolt rifles will group equally well with any good ammunition. I have told on here before how I was once building up a load for a 30-06 with 180 grain bullets and 4350 powder. At the range I loaded and fired the cartridges one at a time, putting one more grain of powder in each case. The fifth load was too heavy, so I decided to back off. Looked at my target, five shots, with the fifth four grains heavier than the first. All five made a 1¼ inch group at 100 metres with my hunting rifle.
I have been bedding my own rifles for more than fifty years. During that time I have bedded rifles for other shooters, including one who was shooting the full wood Lee Enfield in match competitions.
Another fellow shooter got a Remington 700 for the competions we were in at the time. He was not too happy with it and asked me if I would check the bedding for him. I tweaked it and there was a good improvement.
As an argument that the ammunition does not have to be tuned to the rifle, I use the cases of big time match shooting. Every military power has, or did have, a match shooting team. They picked their top shooters, gave each one a well tuned rifle and supplied the ammunition, usually special match ammunition.
If one of the shooters rifles was not shooting well, would he say he needed some different ammunition, something his rifle "liked?" Ha Ha Ha. His rifle would be sent to the armouror for tuning, usually bedding.
On another thread Ganderite stated he had an order to make 40,000 rounds of match 308 ammunition for a police shoot. Did they state the ammunition had to be of all different loads, so they could match up every rifle? I think not.
All of this is to point out that the case of the rifle written about, to start this thread, should be bedded!
 
H4831....I will bring that up to him like you said with your rifles his shoots just about everything else he feeds it great except for this batch of reloads. He's shot the identical load components loaded by a friend and it shot and stills shoot those loads at 3/4". The batch he loaded up shoots up and down everytime. He can shot a 3" vertical group with that ammo he loaded then shoot the same load that a friend loaded and its down to nice round 3/4" groups. That doesnt sound like a bedding issue or an issue of "untuned loads". As far as full length Vs neck sizing thats not an issue. What we were talking about was plain not resizing new brass at all that has been kicked around in a bag. I've got new brass that the necks on some of them looked egg shaped before resizeing. I'm sure a loading a case with an egg shaped neck wont help with the accuracy and we were wondering if that would casue whats happening.


Thanks
Tim
 
H4831 said:
I think a well tuned rifle will shoot any good ammunition well, unless there is something basically wrong with the rifle.

I generally agree with this, as long as you are staying with a load that makes sense for your rifle. But I don't agree that you won't get variation between loads. The thing that struck me with what was described is that the rifle shot well with factory and another reload.

If one of the shooters rifles was not shooting well, would he say he needed some different ammunition, something his rifle "liked?" Ha Ha Ha. His rifle would be sent to the armouror for tuning, usually bedding.

Tuning involves more than bedding, of course. I bed all my rifles, but still work up loads for each one and there are fairly large differences in performance with various loads. My old 308 Sportco for instance would group between 3/4 MOA and 1/3 MOA depending on which load I used. I know bedding can be spongy or poorly done too. But it isn't necessarily first thing I think of and if the rifle feels right when it locks up and I can't feel any movement when tightening the locking screws I'm good to go.


On another thread Ganderite stated he had an order to make 40,000 rounds of match 308 ammunition for a police shoot. Did they state the ammunition had to be of all different loads, so they could match up every rifle? I think not.

I assume they do this to start from as level a playing field as possible and the accuracy being demanded is compatible with the procedure. They are probably looking for adequate performance with consistency and speed rather than subminute groups. Not to say there won't be guys that do it.

All of this is to point out that the case of the rifle written about, to start this thread, should be bedded!

This is not always the first thing I look at and I wouldn't spend the time and money doing it until I was sure that was what was needed. This particular rifle has been presented as 3/4 MOA with other loads and both guys can do it. There is a question in my mind why the stringing is occurring with one particular load and why bedding hasn't affected them all.
Click to expand...
 
This case is bewildering! I guess the reloads that won't shoot should be taken apart, just to see if everything is as it should be, or make new reloads.
Another thought, are the reloads that won't shoot the only ones made on his press?
 
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