Recently purchased a Rem. 788 in 7mm08. I mounted a Leupold VX-II 4x12x40mm on it. I took it to the range and it was all over the place using 3 brands of factory ammo. The trigger was extremely heavy and the stock was hitting hard on the barrel for the first 5 or so inches. I installed a Timney trigger and free floated the stock all the way to the receiver. I installed the stock and torqued it to 45 in. lbs. It came with a weaver one piece base. I installed weaver steel rings torqued to 25 in.lbs. The barrel was clean and bright. Took it back to the range ..... same thing !

I'm not sure what you mean by being all over the place. Group size? What does your group look like? Round. vertical or horizontal string.

A few possibilities.

The barrel/throat might be shot out.
The crown may be scored/damaged.
The scope may be broken.
The base or rings may be loose.

Bad scope
Loose or broken scope mount or screw
Cracked stock

You've made a start. Keep looking.

DPD, I have a 788 in 308 to which I've done all you mention plus bedded receiver with JB weld and torqued stock to only 30 inch pounds. Shoots my 150 gr Accubond handloads between 1/2 and 3/4 " using close to max charge of Varget. The older birch or whatever it is stocks can easily develop hairline cracks near action screws and in web between trigger and magazine so I made sue to bed these areas and torque like I said. Works for me. Also, likes to shoot a fouled barrel but only about 20-25 rounds and then a thorough bore scrub with a good product. Good luck! Mac

Trying to post a pic of the target. Pretty much a pattern instead of a group. I cannot see any cracks in the stock. 3" group at best. Right, Left, Up, Down.... whatever it feels like doing. Does the same thing with me or my son behind the trigger on a solid rest.

https://www.24hourcampfire.com/ubbthreads/ubbthreads.php/galleries/12403526/target . Picture is not correctly orientated . Should be rotated to the right ..The writing on the bottom of the target ( dirty bird ) should be facing you. The seven shots closest to the center were fired without any adjustments made to the scope.

I had one in .243 that did that. I ran through way too much $ in factory ammo trying to find something it liked. Everyone on the inter web said they were amazing shooters, but I couldn't make it happen. A call to the late Mickey Coleman brought his diagnosis of a "bad barrel". He rebarrelled it with a Douglas for a ridiculously low price, and now it's the best shooter in the safe. I really miss that guy.

Anyhow, I'd not have bothered with the trouble & expense, but Dad gave it to me when I was 12.

Hope you can get yours figured out.

FC

Seems to be vertical stringing. Almost like two levels, an upper and lower There are a few things that cause this. Rifle grip or scope/mounts that are loose or broken are often the culprits.

You can recheck your scope, mounts and rings.

You might be putting a death grip on the stock. Muscle tension and twitching will string the groups out horizontally. This is usually more of a problem when using a bipod than with a rest. Inexpensive rests tend to string more than one that anchors the forestock.

One problem I found that's unique to the 788 is that the rear action screw threads can bottom out on the receiver, and not hold the rear of the action properly. The threads on the rear action screw may not be threaded far enough to achieve proper clamping before the screw threads stop in the rear screw boss on the receiver. One fix is the thread the rear action screw further up on its body. Another choice might be to put a spacer (washer) between the rear screw hole in the bottom metal and the stock.My rifle had this condition. I added the washer and it helped a lot.

The other thing I did was recut the muzzle crown. There was visible damage to the original crown. A brass 1/4-20 round head screw and lapping compound in an electric drill worked for me.

My 788 tends to copper foul, so it shoots best loaded with CFE223 and a 165 gr partition.

I have a .308 M788 that was driving me crazy until did these fixes.

I see the same thing with the two groups.

I wonder of the lower group are the first shots and and the upper group is with a warmer barrel?

And yes, the first thing I would try is to pull the scope and mounts off, check them closely, and remount the scope.

Those were not fired in two groups . The shots were all over the place . One shot high , the next low , the next left , etc. Literally all over the place. I wish I could have numbered my shots but the range was busy and I had 2 guys waiting on the lane .

It might just not like those bullet weights and or the loading.

I would just go over everything one more time.

I don't have much luck being in a hurry. Put a different scope on. IMO. Rule that variable out.

I have been shooting my 788 in 7mmo8 since 1984 I also have 6 other 788's in different calibers. The only ammo I could never get to shoot good was the premium stuff.140 gr remmy or 140 gr Winchester always shot great. I reload for the old girl now and I can't make a bad load. This leads me to believe there is a problem somewhere. A dirty barrel has sold more guns than Obama becoming president! Make sure the barrel is clean and I mean clean .Take it to a gunsmith and have him scope the barrel to see how clean it really is.
Shiny bore means squat. Copper is shiny and that's your enemy. Get some good copper remover solvent and start scrubbing.

I did scrub the barrel with Hobbs # 9 . I will try to clean it again with copper remover. As far as ammo , I've tried Rem, Corloks 140 gr. , Whinchester Super X 140 gr. and Hornady SST's 139 gr. I'm in the process of replacing the scope base and rings and trying to find a scope to try without having to pull one from another rifle. I've gone over the stock at least 3 times with a magnifying glass and cannot find any cracks. I also re torqued the stock to 30 in lbs.

Clean the barrel well with Montana Extreme or Wipeout or Patchout. Use a synthetic bore brush. Once a patch comes out clean use JB Compound. Take a patch, "roll" it onto a bronze bore brush of a smaller caliber, slather some JB on it and 10 strokes down the barrel. It will come out black. Clean the barrel again with solvent.

Find a gunsmith in the area that has a borescope and pay him a fair price to take a real look on the inside.might just save you a lot of time and headache.

This may be an easy check. Loosen or remove the front action screw and check for movement.