Load testing question

[its only light]

Hey guys,

I'm back with another question. I recently started shooting my new/used build. I'm in the load development stages now. I've done load work up for a couple rifles now and I really haven't had many issues.

I went out and tested my first hand loads and accuracy well left alot to be desired. I encountered alot of vertical stringing on every load I tried. My best group was .770 at 100 yards and my worst was a little over an inch.

Every other time I've done it I've loaded up a range of powder charges and 1 or 2 always shot noticeably better than the rest. I'm wondering is there something I could be doing in my loading to get the vertical or should I be looking elsewhere such as bedding for the issue. My other question is I tried a powder that has very little info so if I tried a different powder could that have the ability to shrink my groups dramatically. Keep in mind I've never had to experiment like this with components. My 308 wouldn't shoot anything over half moa and basically the same with my 223 so it's hard to imagine that a powder change could shrinks groups a ton

 

[BoydAllen]

We need more information about your rifle, load , and rest. Have you run your loads up to the level where you are seeing some pressure? Has the rifle been bedded? If it has, how did you check to see if it is correctly done? How much free float clearance is there between the barrel and stock?

 

[its only light]

Yeah my post was getting long and I didn't know if it mattered. My rifle specs are as follows:
Savage RB/LP target action
Obermeyer M24 contour 27" 5r (setup with no nut) chambered in 284 win
Bedded in a bell and Carlson A2 stock

This is my first gun that wasnt complete when I bought it. My load was as follows.
Hybrid 100v
Win brand brass
162 amax
Winchester lrm primer

I started from book mid 49.0gr and worked to max 54.0 in .5gr increments.

At 54.0 the bolt was still easy to open there was no real signs of pressure. That being said the book oal length was 2.9 inches and my oal was 3.07 which was a .02 jump in my gun. I'm not real familiar with the long throat so in not sure if that just raises what the max charge is or if its more complicated than that. The book shows 54.0 as compressed. It wasnt in mine.

The other thing is I also have H4350 and rl17 and I also have Sierra and Berger 168's to try. I was hoping hybrid 100V would work because I can find that everywhere here. I'm wondering if powder alone can affect accuracy that much or if I have other problems. As far as checking the bedding I guess I could use a little advice how to do that. One thing I thought I knew about bedding is that you only want the recoil lug to contact on the rear face. My gunsmith has it contacting all the way around and on the bottom of the lug. It's actually a tight fit to get the lug in the slot in the bedding.

 

[bigedp51]

The main page of accurateshooter.com is a wealth of information.

Savage Action Screw Torque Tuning (It even works on non-Savage rifles)

http://www.accurateshooter.com/technical-articles/savage-action-screw-torque-tuning/

And it "might" work with Lee Collet dies. :

 

[BoydAllen]

I disagree with how your gunsmith beds. Beyond that, I would drop back to the middle of the book range for powder charges, and retest with your bullets about .010 longer than just touching, accurately measured. It may be that with the jump and powder that you are using, that you are not getting into the pressure range that you need. I pretty much always do my initial workup seated somewhere into the lands, if throat length permits. Getting back to the bedding, on a Savage, I am of the opinion that the tang should float, and that playing with action screw torque may show some improvement, especially with three screws. Did your smith install pillars when he bedded it?

 

[amlevin]

To avoid shooting up a lot of trial and error loads start with a simple ladder test.

Here's a write up on one of the most widely used methods

http://www.desertsharpshooters.com/manuals/incredload.pdf

Once you have determined the accuracy nodes for your rifle then you will know what areas to work within.

Beats just throwing "stuff" against the wall and hoping some will stick.

With every new rifle, and each component combination I use in it, I start with an average of 10 loaded cartridges with loads spread from minimum to published max. Once I find the sweet spots then I fine tune by shifting to 3-5 round groups for charges close to those ID'd in the ladder. With my .308 I usually work above or below by .2 gr per charge. It's rare to not find a sweet load in 50 rounds or less.

 

[its only light]

As far as the pillars go the stock has the aluminum vblock so he skimmed that portion and bedded the lug. He Also went about an inch up the barrel as well. This is the 1st experience I have had with this gunsmith. I will check when I get home but I'm not real sure the tang is floated either. If not to I just relieve that area with my dremel?

 

[Lapua40X]

Recheck the torque on all screws -
Don't overlook the shooter - consistent shoulder hold position, trigger pressure, grip, etc. are all factors that can contribute to vertical stringing. Inconsistent placement of the rifle on any rest (sand bags, etc.) can also be a factor. Do you use a butt bag? Consistency in placement of that can also be important.

 

[its only light]

Shooting prone from a bipod. I have enough confidence in my skill to know I can hold better than it was shooting. That being said it was cold and windy and that definately could have

 

[Alex Wheeler]

I would try shooting off a sand bag and see if that helps. Not saying you cant shoot well with a bipod, but I have seen them induce a lot of vertical.

 

[broncman]

Try a different primer than Win LR! They open my groups up.

Rear bag techniques from prone Postion have caused me vertical. especially with something that has some recoil..

 

[its only light]

Hey I'm not too cocky to believe it couldn't be me. I will give the bags a shot once. I also have some rem 9.5 mag primers I will try. Unfortunately all I could find was a box of 1000 Winchester mag and 1000 Remington mag primers. Could it be that I'm using magnum primers?

 

[its only light]

Just to update the guys that were helping me out here. The tang is not free floated.

 

[BoydAllen]

Why the mag primers for an '06 capacity case? I think that something milder might be a better choice. Also, I am not to big on bedding the barrel. You can use anything you want to remove the material under the tang. You want clearance for a piece of paper with the action screws tight. I always do a pressure series with the bullet showing light rifling marks, and FL sized cases, running it up to the point where the bolt lift is a little snug, noting the temp. and using something below that for my top load....at that temp.

 

[its only light]

The mag primers aren't really by preference. I only have about 50 cci large rifle primers left and the two 1000 boxes of mag primers has been all I can find. It was never an issue so I never had tons on hand and i got caught with my pants down when it came to stocking up. My reloading manual showsost of the 308 win data using mag primers. I asked a question on the forum about it and turns out many people use them in these mid size cartridges. Don't know if it would be a reason for the loss of accuracy. Maybe I should sacrifice my standard primers to see if it shoots better. Didn't see much use in working up a load with them if I don't have more. I am going to float the tang tonight.

 

[Alex Wheeler]

One other thing came to mind. I have had barrels than exhibited vertical in every load with some powders. I still have one. Try a different powder.

 

[mr45man]

Although it might not have anything to do with your problem
The the bottom of the recoil lug should NEVER bottom out on the bedding.
John H.

 

[its only light]

As far as the powder causing vertical stringing I've been wondering if that could possibly be it.

In regards to the lug it's always been my understanding you want clearance on all sides but 100% contact on the rear face. Basically what you said. Mine definately hits on the bottom and all sides for that matter. I figured the gunsmith new better than I did so didn't say anything. Maybe I should relieve that while I'm floating the tang tonight?

 

[BoydAllen]

The last time I did that (years ago) I made a scraper out of a cheap screwdriver that was a little narrower than the thickness of the recoil lug, to scrape the bottom and sides, being sure to work back into the corners. (sharpen and roll the edge to one side) It is also a good idea to cover the back of the mortice with tape to protect it while you are working. Work slowly and carefully. Another thing to look for is whether any of the bedding squeezed into the action screw holes in the stock, the screws should not touch the stock at all. They should only touch the floorplate, trigger guard, or escutcheon, and the threads of the action, nothing between. also a well done job includes bedding the trigger guard. If you think about it, with a free floated barrel, the back screw, and middle one for that matter, are being pulled upward, and it is the trigger guard or escutcheon that take the weight of that pull, so the surface that the trigger guard rests on should be bedded for even contact. On your a savage, particularly because there in not support all the way around the rear screw, you should snug up the front screw first, working to the back, and as you increase torque to your final setting, do the same thing. Personally, I would scrape some clearance between the stock and the back of the barrel. That action is plenty stiff enough to carry that barrel. (IMO)

 

[searcher]

Not to take anything away from what these knowledgeable folks have said - but all rifles will react to how much of the barrel is bedded as it will change the harmonic vibrations of the barrel when more (or less) of it is bedded. Because in an area where bad bedding can affect accuracy worse than where no bedding is required and thus there is no such bedding, it can give the impression that no partial barrel bedding is always best - and this is not so. Bad bedding is that which allows inconsistent vibrations much like allowing the action to be loose or a guard screw touching the stock. You want the right vibrations (mostly attained from your load development results) and for them to be repetitive. Given that you have a ridgid stock with the aluminum channel, as long as your action screws are SNUG, you have good, solid bedding and no action screws touching anything other than your bottom metal, it is also doubtful to me that a fully bedded recoil lug would be the origin of your problem. If your bedding appears worn and there can be ANY discernable movement of the action once you snap it into your stock (without screwing in), your bedding is suspect. Most serious match shooters utilize "glued-in" actions to alleviate such problems. (There usually is full contact all the way around the recoil lug) When an action is difficult to remove such as yours - it is likely the good tight fit you want. I say this because I have done load development for more rifles than I can count over the past 40 years and I can assure you powder selection (as does primer and brass, seating depth, bullet selection, etc.) can absolutely cause a 1" vertical dispersion in a good rifle with absolutely no bedding or other problems. A key indicator of bedding problems is usually when this dispersion pattern is erratic. To repetitively get groups that are vertical and similar in shape and size is not by itself indicative of a problem. It can simply be telling you that you are not on the vibration node that works for your rifle yet. Do the ladder tests at 200+ yards, don't increase your powder by more than 3/10 grain per change, check to be sure your brass is headspaced to within .003" of chamber, powder charges reasonably close to within 1/10th grain, use a powder that best fills the case capacity, that your brass is trimmed at least .005" short of your chamber and you will have eliminated many of the common things people routinely have happen to them which creates such vertical problems. I noticed you mentioned new/used when referring to your build. If the barrel is not new - check with borescope if available and give an extra good cleaning with copper remover if heavy copper is found. Good Luck!