I’m having accuracy issues with my Remington 700. The specs of the rifle:
Remington 700 SPS-AAC Tactical
Bell and Carlson stock
EGW base
Burris Xtreme rings, extra low
Vortex 5-15x 44mm scope
Timney trigger
AAC muzzle brake (suppressor adaptor)
AAC SDN-6 suppressor
Harris swivel, notched bipod
Karsten cheek riser
I included a picture of my incomplete round count records that includes some of the rifle’s performance. It started off not so great at 1-1.5" groups and I started making mods. I don’t have track of all the mods but after the stock upgrade it started shooting well to the tune of ~.43" groups. I’m not sure what changed but all of a sudden it started opening up the groups again. I suspected it might have been the installation of the AAC brake and after reading a recent accuracy issue thread I removed the brake (installed with shims) and reinstalled with less torque. I also disassembled rifle and reassembled with proper torques. Stock torqued to 50 in/lbs.
I went to the range recently and shot a few 1-1.5" groups and ONE outstanding group of about .25" all with Federal Gold Medal Match 168gr (SMK’s). This was all unsuppressed. The .25" group was shot somewhere in the middle of the bad groups. When I saw the groups opened up again I went over the entire rifle checking the tightness of all bolts including the base screws. Nothing was loose or appeared to have changed. I have swapped scopes and bases previously in search of the issue to no avail. The fact that I shot such a good single group makes this extremely confusing to me. Any help here is appreciated. I have included pics and screen shots for analysis.
This may be due to any one or a combination of these
Fouling, but your round count isn’t that high. What is your cleaning routine like?
Ammo (already mentioned).
Technique
Rifle (and bipod)
Shooting three round groups
I’d suggest refraining from getting too hung up on making direct comparisons in spread, i.e., group size, from three-shot groups- particularly when you get a single “ringer” (likely spurious statistical event) among several larger groups shot from the same load/ammo. Go shoot some five or 10 round groups using 175, 168 (perhaps some 155 gr such as Nosler CC) ammo from the same lots and see if you see a trend. Try shooting off of sand bags or similar as well. Personally, I can’t shoot consistently well using a Harris swivel not matter how hard I torque the locking lever. With a good rifle rest my SPS would shoot with more horizontal variability than vertical (though yours may very well be doing that as well) which was alleviated by bedding. Like you, I fiddled with torque on rings, bases and action to no end. My rifle also favored like lighter, e.g., 155 and 168 gr bullets even with the fast twist barrel.
At the end of that fiasco, I ended up with a solid .75 MOA stock rifle using factory ammo and ~.6 MOA consistently using hand loads. Decent for a factory rifle.
I have no first hand knowledge but have heard it claimed that the AAC brake may be the culprit. That is, when shooting unsupressed. You might want to try removing the brake and trying again. Or just shoot for groups suppressed if that’s why you’re running the brake. If you don’t have the can and just want to run a brake, I’d try the Surefire model instead.
Well the weight of that mount alone could impact the barrel harmonics… so you wouldn’t want to simply say the brake is a problem.
Those mounts are somewhat heavy and could cause the shooter to have to alter the load to get back into a groove. We’ve not had that happen… but it’s possible.
What bottom metal? If it’s the stock cast POS, check it for cracks. I replaced mine with a steel unit from Stockys, torqued to 65 inch/lbs. Also, I had to bed the bottom metal to my B&C stock.
FWIW, my 700 Tac SPS (20 inch barrel, 1:12) shoots the Federal 168 loads extremely well off a solid bench and bags.
I still have the stock bottom metal installed. The stock is not bedded to the receiver or bottom. I have now replaced the AAC brake with the DPMS Miculek brake I had on it when it was shooting tight groups (although it weighs as much, if not more than the AAC). This rifle is a 1:10 twist, I should have mentioned that in the original post.
I just don’t understand how it can shoot good groups sometimes and not others. And the good groups are a similar tight spread and the large groups remain similar in spread size. I apply a simlar technique each time I shoot: prone, shooting mat, loaded bipod, bag rest at rear of rifle.
Markm (and others), is it not recommended to load the bipod off grass or concrete? I do agree it slides a bit loading it on concrete but I’m usually digging it in the ground/dirt. More comfortable, too I will try the replacement brake installed next outing and try a larger variety of ammunition. I will also bring the factory thread protector if the Miculek brake doesn’t change anything for the better. If it doesn’t shoot well then should I bed the stock next?
At least in my case, it seems the receiver sits very well in the B&C aluminum block, with even contact. The issue I had was with the inletting for the trigger group, it was uneven around the rear screw such that when tightening the rear screw, I could feel the trigger guard flexing before I got solid contact on the rear pillar. Bedding the trigger guard resolved that issue.
IMO, it doesn’t seem like anything with barrel harmonics or ammo. I would make sure that the recoil lug is in full contact with the block (tighten the action screws with the barrel facing up), that there is no contact between the barrel and stock and that there are no issues with the scope mounting (or the scope itself).
BTW, did you bed the scope base? The Remington receiver is notorious for uneven finishing on the top/rear resulting in stress if you just sock the mount screws down. Google “bed Remington scope base” for plenty of reading on the topic.
Finally, I would shoot with the barrel fully naked and see if that makes any difference. The 1:10 twist may prefer the 175s.
Good luck, with some patience you’ll get it tracked down.
Make sure the scope cap screws are tight my co-workers FN bolt gun w/34mm Steiner wouldn’t shoot better than 2.5MOA until I torqued the scope cap screws to 22in lbs, now shoots sub-MOA.
Yes, I have bedded the scope base. I will try naked barrel(along with other muzzle devices) next trip and report back. I’ve put some nice groups together with 168’s multiple times but I’m pretty sure I have some 175’s around and will try them and some others.
Did bedding the bottom metal improve the accuracy/consistency for you?
Robb, I’ve verified the ring’s caps screws are tight but I’ll still check with a torque wrench.
The rifle shot at least .7 MOA every group, with about half of the groups .5 MOA or better before I bedded the TG. Since that time, along with bedding the TG, I reduced the trigger pull (Timney 510) from 3.4 lbs. to 2.1 lbs., added a sunshade to the scope, added a cheek riser for better eye-to-scope alignment and finally have the eyepiece dialed in to render the reticle razor sharp. It’s actually amazing how sharp the reticle is in the SWFA scope now that I have it adjusted properly, probably sharper than any other scope I have ever owned.
I haven’t fired it again since all of that has been done, but will be within the next few weeks.
Alright, I made it back to the range yesterday armed with the advice from you fine fellas. I couldn’t find all the other .308 ammo I have in my house so I only shot 2 loads. A failure on my part but will remedy this next range trip. All groups are Federal Gold Medal Match 168 gr except the last is Hornady Match 168 gr. I obviously lacked diversity here.
Rig:
First two groups were shot with no muzzle device installed:
The next group I installed the DPMS Miculek brake that I’ve had success with in the past:
Not happy where that was going I installed the AAC 51T brake:
Looking better, I decided to affix my 762 SDN-6 suppressor:
Last, I tried the Hornady Match 168’s to find there were only 5 rounds left in the box. Said box is obviously now empty:
At least it appears to be less erratic and I will be bedding the receiver to the stock (and possibly the bottom metal) as soon as my Devcon arrives in the mail. Any additional suggestions are very much welcome.
Looks like your doing better now, But I have never liked action bedding blocks. Something about them just gives me the heebie jeebies and I have never seen identical rifles save bedding methods were the v-block has out performed and good bedding job done with marine - tec or any other comparable material.
Something too look at would be the torque of your action bolts, I’m sure you know this but once I find the load that my rifles like I start looking for the preferred torque. You would be stunned at just how much more accuracy you can ring out of a rifle that way. Although I’m a really big fan of glued in actions as well.
Barrel harmonics are as close to black magic as I have ever encountered in my life though. I’ve run barrel tuners and action blocks on my bench rest and f-class rifles for a long time and it is absolutely scary how just a grain of weight on the muzzle or just the order the action block was torqued will affect zero and poi, much less group size.
If I can ask though, what is your cleaning regime. I’ve found that most of my Remingtons’ really didn’t shoot that well until they were pretty warm and had about 15-20 rounds to foul the barrel.
Sorry for any grammatical errors, this was typed on my phone.
Looks like you are getting there. Your probably responsible for .25 moa and your gun is doing another .5 inch. Therefore, your gun is doing fine. How fine is your reticle? Some of my scopes have thicker lines and are more difficult to shoot very tiny groups.
Don’t clean your gun but every 200 rounds or so. Some people believe when you change rounds, therefore changing powders, sometimes the barrel needs to be “seasoned” with new powder. If your first group after changing rounds is large, just keep that possibility in mind.
It’s interesting you only took two kinds of ammo and got your best groups. Just run either of those last two choices, maybe buy 50 rounds of that last choice- Hornady match- and stick with it a full day.
Best of luck.
Sorry about that. Feel free to question anything I say if it isn’t clear enough, I have a very hard time making my point come across when it comes to any form of communication, especially when technology and typing is thrown into the mix.
I dont like bedding blocks for the simple reason that you only have two very narrow points of contact with the bottom of the action. Production actions aren’t very consistent in the inside or outside diameter so unless the outside of diameter of the action has been trued, there is little to no chance that the block and action have one hundred percent surface to surface contact.
Because of this, every time the rifle is fired the recoil pushes the action back and forth on the action in no predictable fashion and will never return to the same place twice in a row.
Bedding the action and pillars with material like devcon basically molds the action to the bedding and creates one hundred percent contact with the recoil lug, pillars and the bottom of the action. The “springiness” of the bedding material also prevents the barrel whip and harmonics from reverberating up and down the length of the rifle as well, whereas the bedding block acts just like hitting a hammer on a anvil.
I know a lot of people love bedding blocks and swear by them, but the only truly accurate rifles I have seen with them were palma rifles that were built custom actions and the blocks were milled to fit them.
PappaBear, I’ll try to stick with a good ammo when I find it. My cleaning frequency is pretty slack: I clean rarely. I am open to recommendations here. I just like to keep moving parts wet in most cases. My reticle seems to be average but I will make another attempt at focusing it.
Avtech, thanks for the clarification. Your description is now very clear. I will practice bedding on a cheaper rifle I have and then bed my 700 with Devcon.
Agreed and you may even find similar or even better results with lighter bullets, e.g., 155’s at 100 yds due to quicker stabilization. Typically should be a wash with factory ammo, however.
I haven’t seen enough data to conclusively evaluate the variables you’re looking at. Are the groups you posted the entire lot or a just the better ones? If the former they’re not that bad, but obviously not meeting your expectations. More data points would be helpful to determine if its the rifle, muzzle device, shooter. or combination thereof.
What kind of experience do you have behind the trigger? Not an attack, just gathering info. Do you have, or have you had, a rifle that consistently shoots 5+ round groups at < .75 MOA?
I will try the replacement brake installed next outing and try a larger variety of ammunition. I will also bring the factory thread protector if the Miculek brake doesn’t change anything for the better. If it doesn’t shoot well then should I bed the stock next?
