Have a Rem 700 with Hart 26 inch barrel. Have been using Lapua brass, Berger 168 VLD bullets, Win primers and 40gr of Vhitavouri N150. At 100 yds consistant .75 inch groups. What can I do to improve. All cases are trimmed to 2.007 and I shoot from a bench. I weigh each charge 2 times.
308 accuracy
- Thread starter Poconolg
- Start date
jwrowland77
New member
Sort bullets? Neck turn? Sort brass by capacity? Measure bullets base to ogive and sort? Uniform flash hole? Uniform primer pockets?
My match loads generally give me 5-shot groups from .15"-.25" at 100yd.
My match loads generally give me 5-shot groups from .15"-.25" at 100yd.
jwrowland77
New member
So, none of the above stuff?
Whatever you do, make each round exactly like the one before. Consistency equals accuracy. You can dive in as deep as you want into the case prepping as you want, but it's mainly just making everything consistent.
Whatever you do, make each round exactly like the one before. Consistency equals accuracy. You can dive in as deep as you want into the case prepping as you want, but it's mainly just making everything consistent.
The most accurate .308 Win. reloads have always been with full length sized cases. That's what commercial match ammo is when you shoot it.
Sierra Bullets does no bullet sorting, no case prep or sorting whatsoever, meters powder charges to a 3/10ths grain spread and full length sizes all their .308 Win cases in Redding full bushing dies. Their best 30 caliber match bullets go into 1/4 MOA in their 200 yard test range.
I doubt all your groups are .75 inch, but if they average that, it's pretty good. Considering the fact that your own variables probably contribute more to the group size than the rifle and ammo does, how the barreled action's fit to the stock may not let one shoot it any better. Especially when the rifle's not held exactly the same way for each shot; which none of us humans do hand holding one against our shoulder.
If the bolt face is way out of square, that can easily cause poor accuracy. All the cases fired with that condition will have out of square case heads and when indexed different ways in the chamber, it'll add 1/3 to 1/2 MOA to whatever the ammo and barrel is otherwise going to produce.
You might try shooting slung up in prone with a bag under the stock's fore end and toe; most people shoot smaller groups that way than from a hand held rifle resting atop something on a bench. Just be sure your scope's far enough forward so it won't bounce off your aiming eye brow from recoil.
Sierra Bullets does no bullet sorting, no case prep or sorting whatsoever, meters powder charges to a 3/10ths grain spread and full length sizes all their .308 Win cases in Redding full bushing dies. Their best 30 caliber match bullets go into 1/4 MOA in their 200 yard test range.
I doubt all your groups are .75 inch, but if they average that, it's pretty good. Considering the fact that your own variables probably contribute more to the group size than the rifle and ammo does, how the barreled action's fit to the stock may not let one shoot it any better. Especially when the rifle's not held exactly the same way for each shot; which none of us humans do hand holding one against our shoulder.
If the bolt face is way out of square, that can easily cause poor accuracy. All the cases fired with that condition will have out of square case heads and when indexed different ways in the chamber, it'll add 1/3 to 1/2 MOA to whatever the ammo and barrel is otherwise going to produce.
You might try shooting slung up in prone with a bag under the stock's fore end and toe; most people shoot smaller groups that way than from a hand held rifle resting atop something on a bench. Just be sure your scope's far enough forward so it won't bounce off your aiming eye brow from recoil.
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jwrowland77
New member
They should. Lol. Horrible consistency in weight as well as consistency in base to ogive measurements.
It helps sorting. I didn't get the accuracy I am now until I started sorting. I finally got tired of it and went to Hornady bullets which I have found are more consistent. That's why so many folks use Bergers in F-Class, consistency. I know it made a difference at the 600yd and 1000yd lines. Along with reducing runout.
JW, maybe the other bullet makers should make their stuff to the horrible consistency in weight as well as consistency in base to ogive measurements Sierra does so they'll shoot as accurate as theirs do. I doubt Sierra's "horrible consistency in weight as well as consistency in base to ogive measurements" are as bad as you think. Otherwise, they would not shoot as well as they do. Would they? Really?
JefferS, Sierra does not work up loads for each lot of components; they use the same load all the time for a given cartridge and bullet across all their test barrels. Many people use the same load with the same components across several barrels and get the same, great accuracy with everything. I've found all the same popular loads winning matches and setting records shoot as accurate in my barrels as they do in others. If the same load doesn't shoot well across so many barrels, then why does the same lot of commercial match ammo do so well in all of them?
JefferS, Sierra does not work up loads for each lot of components; they use the same load all the time for a given cartridge and bullet across all their test barrels. Many people use the same load with the same components across several barrels and get the same, great accuracy with everything. I've found all the same popular loads winning matches and setting records shoot as accurate in my barrels as they do in others. If the same load doesn't shoot well across so many barrels, then why does the same lot of commercial match ammo do so well in all of them?
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jwrowland77
New member
Well, based on the thousands and thousands I've weighed and measured for my match ammo, yes they are that bad. It's one of the biggest reasons I switched bullets.
I figure the less I have to worry about it, the more time I can spend somewhere else like practicing or with family.
I figure the less I have to worry about it, the more time I can spend somewhere else like practicing or with family.
Cool. I wasn't clear on how you got to your seating depth, etc. I haven't had my Rem 700 SPS 26" for that long and haven't spent years on working up a load. I need to spend more years practicing, because I'm my own limiting factor right now.
I'm using Sierra, by the way, with IMR-4064 for my match loads.
I had pretty significant differences when I did OCW testing on my Sierra MK 175 gr a few weeks ago. Seemed much more than what I was introducing with my skill.
Again, I was just not clear on how the OP worked up the load he listed (both powder and seating depth). With just the recipe listed and 3 posts to this forum, I thought he might have been a new reloader who got a load from a buddy and never did anything like OCW or worked up powder. So I just thought I'd ask the question to clarify to myself. He's obviously an experienced loader and I can't help someone who is probably a lot better than me. I have no ideas about barrel deterioration since I haven't shot a barrel enough to do anything to it. I'll leave the advanced stuff for the advanced folks.
Again, I was just not clear on how the OP worked up the load he listed (both powder and seating depth). With just the recipe listed and 3 posts to this forum, I thought he might have been a new reloader who got a load from a buddy and never did anything like OCW or worked up powder. So I just thought I'd ask the question to clarify to myself. He's obviously an experienced loader and I can't help someone who is probably a lot better than me. I have no ideas about barrel deterioration since I haven't shot a barrel enough to do anything to it. I'll leave the advanced stuff for the advanced folks.
There is no shortage of Sierra bullets around here. I repaired a RCBS 3 poise scale, to test I started on Sierra bullets. I selected 5 boxes of bullets ranging from 100 grain to 150 grain. From the first box of 30 Cal 150 grain bullets the first four bullets had a spread of .4 grain. I was not testing bullets I was testing the scale.
Then there is the capo, a fancy Italian word for clamp. I do not clamp my rifles to the bench by the barrel with the receiver hanging out the rear. I do have one rifle that was voted as 'the ugliest', $120.00. I took it to the range and decided to apply the 'leaver policy', I leafter the way I founder. Not bad for a parts gun.
I have no clue what happened to the old saying 'What does the rifle like'. I built a rifle, I loaded 12 different loads of 10 rounds each. I used 12 different head stamps, different powder and bullets and I used different 'off the lands' loads. None were at or near the lands.
The groups moved, none of the groups opened up and none were larger in diameter than a quarter and some shared the same hole. I loaded another 120 rounds with 12 different loads, cases and bullets and delivered the rifle to the new owner. I ask him to find out what the rifle liked. The rifle liked everything.
F. Guffey
I shoot a Rem 700 308 cal. 20" brl 11.27 twist. Using FC Brass trimmid to 2.010, use to neck size only for years, have changed to full sizing with better success. keep my headspace to .001, using a 168gr. Sierra HPBT with a .012 jump. Shoot 200 yards do to range is max. 200 yards, groups are .5 and better. load is on the low side IMR 4064 40.5 gr. Federal cases are thicker then most. How are you preping & measuring your brass & seating the bullet. What gauges are you using. When the Hart barrel was installed was the rifle blueprinted. Also changed to Redding Type S Bushing die to adjust neck tension, I like them very mush. I also clean after 20 rounds.
I would first want to determine if the .75 groups were the best that the rifle/load combo was capable of. I have a couple of friends who own Lead Sleds, I would borrow one and check groups with it. If the loads were shooting better in the mechanical rest than I could do off the bench, I'd practice more. If not then I would start tweeking the load and my reloading practices to see if I could get it better that way.
Any rifle will shoot a small number of very tiny few-shot groups that are under 1/3 MOA at short range. All one has to do is keep shooting them until one has virtually all the variables cancelling each other out and all those few bullets land almost atop each other. Or, by some stroke of luck, everything's perfect and repeatable for all shots fired in that group. It's virtually impossible to tell which way made that tiny group so small. It usually happens a time or two before the barrel's worn out. The smaller they are, the less likely they'll be shot again that same tiny size.
Poconolg said:
Those could be contributing to the limitations. I'm always leery of such short jumps, as it is very easy for bullet, case, and chambering force variations to alter the actual distance of the loaded round from the lands that much. So you could be introducing pressure variation, which is modulated by distance off the lands more near the throat than it is either in the throat or a bigger distance away from it. A chronograph should tell you. If you are going to make improvements, that instrument is very handy for detecting improved consistency of any kind.
With kind permission from Jim Ristow at RSI, the below shows a little over 20% pressure variation from a 0.030" move from the lands to off the lands, but more of that 20% happens in the first 0.010" of that 0.030", than in the last. This is why I'm concerned small variations in your short jump could be introducing pressure variation.
Berger itself has said they used to recommend all VLD loads be seated to jam into the throat about 0.010". That's an old time benchrest trick to force good bullet alignment, but for reasons not clearly understood, it doesn't work consistently. Berger said its customers found some rifles just would not shoot their VLD's well until they introduced some jump. Sometimes a lot of jump. Read this article on making VLD's shoot at Berger. In part, it says:
Berger said:
They go on to give you a procedure for finding that point. It's less of a problem with tangent ogive bullets than with secant ogive bullets, which is why Berger introduced their hybrid ogive bullet design that starts out tangent at the bullet diameter and then converts to the lower drag secant design after it becomes narrower than the bore diameter of the barrel.
Nonetheless, tangent ogive designs can also be sensitive to position. Writing in the Precision Shooting Reloading Guide (Precision Shooting, Inc. (RIP), 1995), Dan Hackett described a Remington 40X KS he got in 220 Swift that would not group five shots into better than 0.35", and more typically was at about 0.50". Then one day, in switching bullets to seat 55 grain Nosler BT's, he turned his micrometer adjusted seating die the wrong way and got 20 rounds loaded with bullet jump 0.050" off the lands instead of his intended 0.020", before he noticed. He decided it was easier to shoot them for practice than pull them down. To his amazement, these twenty rounds shot about 0.25" with a couple of real bug holes in the high ones. Conventional wisdom he'd been exposed to had been that you never seat more than 0.025" off the lands for best accuracy.
That's a problem, made worse by the Internet, that a lot of folks conclude things that are not scientifically proven. It is usually anecdotal (turned out to be true in his guns). Sometimes its just consensus based on impressions. Actual experimental proof of things can be hard to come by.
I've had a couple of different theories about why tuning seating depth turns out to matter, and aim to prove one or the other as part of this summer's bucket list. One of these is that the change in seating depth changes barrel time which alters where the whip the muzzle is located when a bullet exits. One reason I think that may explain the matter is Bart's example of Sierra's guns not needing special load tuning treatment. I once saw a photo of these guns in an article in Precision Shooting (1998-99?) written by Kevin Thomas when he was still with Sierra. Unlike a rifle in a stock, these were, IIRC, Remington actions mounted in holes drilled through steel angle that was welded to a bench. That angle took the place of a recoil lug, and because of its width, would have been far more rigid. A gun mounted this way will never have a lot of the muzzle whip that loads are tuned to allow for. That is because the whipping is induced by the recoil moment that raises the muzzle. Guns that apply recoil straight back won't have that. It happens in stocked rifles because, except for some bullpup or other less common designs, is due to the bore line being above the center of support pressure at the shooter's shoulder.
Harold Vaughn's book, Rifle Accuracy Facts, proves the above by measuring recoil moments in a .270 Sporter. He then uses various means to eliminate them one at a time. He ultimately mounting the action on a stock interface that lets it recoil freely far enough that the bullet clears the muzzle before it reaches a rigid limit transfers momentum to the stock. He got it to shoot 1/4" 100 yard groups consistently.
Per Bart's comments, I think there is now broad agreement that neck-sizing-only has potential to produce best accuracy only when the brass is nearly perfectly uniform in wall thickness and the chamber is nearly perfectly coaxial with the bore and the bolt face is nearly perfectly square to that shared axis. In most instances, you don't get all the stars to line up that neatly for you. Furthermore, unless the loads are mild, the brass tends to grow slightly with each firing so that it eventually gets so tight it has to be full length resized once more, which means it is a little different in shape at each load cycle. These are reasons using an FL sizing die to push the shoulder back at least 0.001" shorter than it came out of the chamber has generally been found to produce better accuracy.
If you like your neck sizing die, you can get a .308 Winchester Redding Body Die that sizes only the shoulder and body, leaving the neck alone. By pushing the shoulders back 0.001"-0.002" on half your cases, you can make a side-by-side shot placement precision comparison on your targets. It means sizing in two steps, but it doesn't sound like that would discourage you since you weigh charges twice.
The shortening and narrowing allow the cartridge to self-center in the taper of the chamber shoulder when the firing pin drives it forward. If the brass case wall is not absolutely uniform in thickness all the way around, it expands more on the thin side than on the thick side. That means that if you don't size the case down, that uneven expansion forces the neck to be slightly off-center in the chamber. Lapua brass is better than most about this, but if you have measured neck runout, on the Lapua I have it is about 0.001" worst case, which is pretty good, but the body wall runout will be about twice what you see at the neck, so it's not a given that it will solve your problems.
Other places to look:
The chronograph, as I mentioned earlier, is an easy way to see if you are succeeding in improving ignition consistency. One of the most common issues is not seating primers correctly. Some of this due the common mistaken belief that it's best to seat them just until you feel the anvil feet touch the bottom of the primer pocket. In fact, you have to compress them a little further for best performance. This is called setting the bridge (CCI) or reconsolidation (military) of the primer. The amount beyond touchdown by which your compress them, according to Federal, should be 0.002" for small rifle primers and 0.003" for large. In documentation from the 1970's, Remington and Olin (Winchester) had this at 0.002-0.006" for both large and small primers. By 1982 the Naval Ordnance Board Indian Head (NOBIH) had recommendations of 0.002-0.004" for some small primers. Based on those disagreements, if you can measure them, the Federal recommendations, because they fall within the other data, seem prudent to use.
The K&M Primer Gauge tool will let you seat them exactly as specified, but it's is very slow going, as it takes making a zeroing measurement for both case and primer, followed by seating as a separate step. For most people, Dan Hackett's advice on the matter is simplest:
”There is some debate about how deeply primers should be seated. I don’t pretend to have all the answers about this, but I have experimented with seating primers to different depths and seeing what happens on the chronograph and target paper, and so far I’ve obtained my best results seating them hard, pushing them in past the point where the anvil can be felt hitting the bottom of the pocket. Doing this, I can almost always get velocity standard deviations of less than 10 feet per second, even with magnum cartridges and long-bodied standards on the ’06 case, and I haven’t been able to accomplish that seating primers to lesser depths.”
Dan Hackett
Precision Shooting Reloading Guide, Precision Shooting Inc., Pub. (R.I.P.), Manchester, CT, 1995, p. 271.
A point on seating depth that, IIRC, either Dave Milosovich or Dick Wright, writing other chapters of that same Precision Shooting Reloading Guide, pointed out, is that a primer pocket depth uniforming tool was useful because it was remedial rather than because it was an accuracy improving tool. That is, having uniform pockets didn't make a direct improvement, but rather prevented a precision worsening problem that occurs when a primer cup is crushed or distorted by running into a radius at the bottom of the cup before the reconsolidation is completed, or where a too-shallow pocket prevented reconsolidation from being complete while the primer was still above flush with the head of the case.
Lastly, you may want to experiment with different primers. Federal 210M large rifle match primers have a higher sensitivity, but lower brisance than average, so the hot gasses play out a little less violently, which they seem to think is important to peak accuracy. But personally, and despite a couple of misfires out of several thousand, I've been getting the most uniform velocities from the Russian-made Tula primers. They are perhaps the hardest to seat, have burrs on the edges of their cups, but when properly seated have been beating everything else at producing lower extreme velocity spread.