Have a 300 win mag (krieger, manners,surgeon zeiss v8 glass) Broke in barrel properly. Immediately developed load gun shot lights out, After about 200 rounds 2 inch groups now. Very disappointed and looking for any intelligent suggestions. Thanks for any input!

Start at the start.

Check and properly torque all fasteners.

Then check scope & mounts.

Who bedded it?

Could be a number of things,here is some things to check.Maybe copper fouled,do a real good cleaning.Recheck the bullet seating depth.I ran into a difference with some Nosler seconds.One lot of bullets I have the ogive is different with the same weight bullets.The original bullets I was using,I set the bullet .030 off the lands.I switched to another bag,with the die still set the same,it seated those at .010 off the lands.That can cause some pressure problems when loaded near max and cause them to group different.Different powder lots can also change things too.Check and make sure your stock screws are snug,if it's free floated,make sure it still is free from any contact.Scope mounts need to be checked too.

Thanks have rtorqued everything to specs. Robert Gradous did entire build. baldhunter very interesting. Have done several cleanings. Never thought about powder lots. Checked free float. Using 215 gr Berger match hybrid. Thanks guys!

215 gr Berger Target Hybrid

I'd be checking my scope with that much change. That and the free float. powdr

That's the route I'd take... I'd also check to be damn sure the barrel isn't copper fouled. Wondering what the cleaning regimen was with the rifle...??? By any chance is the OP using a Leupold scope???

I'm using a Zeiss Victory V8 2.8-20x56 illuminated # 60 reticle scope

What do y'all recommend for removing copper fouling. I have used Hoppes and also Ballistol so far? Anyone have an opinion on tweaking the load now that the barrel has smoothed out and muzzle velocity increased some? Thanks

Bore tech eliminator for copper! Or bore tech CU copper cleaner!

Hoppes does nothing for copper fouling. Never used the Bore Texh, but heard it works. Sweets is a great copper remover, just use something after it, a light oil.

If you haven’t been using a dedicated copper solvent, it’s prbably fouled horribly, I like the foaming CLP copper stuff, doesn’t get you nearly as screwed up in the head as sweets does... that stuff is nasty!!!

I will try the copper removal products mentioned. Still curious if an overnight soak in ballistol has been effective?

The real copper solvents will reccommend you not leaving them in your barrel for more than 10-15 minutes. They are some really nasty stuff usually smell like ammonia and will give you a ehadache if not used in a well ventalated area.

I always though ballistol was like a rem oil type cleaner/ lubricant, good on powder but not designed for copper.

I did the same thing with one of my first varmint rifles in .22-250, I shot the hell out of it and it started to open up. I started using sweets 7.62 in it and the patches started coming out blue... thats copper reacting with the ammonia and breaking down... remember that copper is being cooked in a 50,000-70,000 PSI pressure cooker and being drug against the rifling at 2-3 times the speed of sound, once that stuff gets into the nooks and crannies your barrel and gets cooked in by a few hundred rounds, its going to take some work to get it out.

Depending on your powder choice it could be that alone. I had a great load worked up with WW 760 in my 300 WSM. It shot lights out the first 5 trips to the range while checking it for repeatability. 6th trip it went away & never returned. Mule Deer warned me about it & sure enough, he was right. Wound up settling on H4350 and I have never seen repeatability like it offers.

+1 for the bore tech products! They work amazing and fast. It's probably copper fouled pretty bad if all your using is hoppes. Sounds like a nice gun with good components and a competent gunsmith. If your not already using these get a coated cleaning rod, nickel plated jag, nylon brushes dedicated copper cleaner and most importantly a bore guide.

Ok gentlemen I'll take the advice and start cleaning and cleaning. Will also try new loads. Seems that's the main two options here by most who voiced their help. Thanks.

I have a work bench with every single solvent known to the US market...I use KG1,KG3 and KG12 followed by KG4(gun oil) another good one is wipeout or patchout in conjunction with their accelerator. I use Ballistol and Clenzoil for my shotguns in and out.

WipeOut is a great product. It is easy to use and does not require scrubbing.

People need to shoot more and give advice less. If a 300WM went from "lights out" to 2 inch groups, it isn't due to fouling. If it is- get a new barrel. We shoot tons of 300WM, 300NM, and 338L and at 200 rounds some have opened up from sub MOA 10 round groups, to 1-1.2moa for ten. Most will go 250-400 rounds before getting a wipe down.






You need to start in this order or you are wasting time-

Action screws degreased and torqued.
Scope base, screws and action degreased and torqued.
Change scopes.



Scopes fail a lot. Even the one you have.

I'm betting it's the scope.

Ok I have a couple of Zeiss diavari and another V8 I can try after following the directions of degreasing and retorque. Thanks

No sarcasm implied or intended, but have you called Robert?

You know the rifle can/did shoot well with the load you have. I have had a couple scopes go squirrelly on me and they went back to the manufacturer, but I knew it was the scope. You can do a ladder test and see if the adjustments work, or put another on it to get that possibility out of the way.

I use a Hawkeye borescope so I know what the inside of the barrel is doing. Robert built a 308 for me years back and it was a rifle that never disappointed. It started to not shoot as well around the 750 round range. About that time, my shooting partner and I purchased a decked out Hawkeye and surprise surprise, it was carbon fouled for the first 6" of barrel (Krieger). It was a pain to remove and I never trusted a clean patch again without having a look. Now, when I stated "not shoot as well", it went from basically a hole for 5 to a bigger hole for 5. I've personally never seen any of my rifles go from their usual accuracy to large groups just from a dirty barrel. Point I'm making in a long winded way is unless your barrel is slathered in copper (it's possible), going from bugholes you say to 2" ain't just from a dirty barrel.

Robert may be "interesting" but he builds fine rifles and knows how they tick.

I used a lot of Ballistol over the years, but only as Moose Milk for my BPCR's. Bore Tech or Sharp Shoot R products have worked well for me for smokeless. I don't trust any of them until Mr Hawkeye says they work.

The preceding is worth every bit you paid for it😁😁😁

Yes sir Robert or his new partner I think John? Will gladly let me send them the rifle to address and correct the problem. Only reason I'm working with my local smith is I'm still a bit skeptical on sending it. Waited over 2 years to get it here to central Texas brand new. Original agreement was for Robert to do barrel break in and load developments but never got that far. J Earl Bridges (my smith) complimented the build after examining everything including bedding. Again wary to send it back to Georgia not having Any way to verify a turn around time.

I do understand your issue with shipping it back and i am familiar with turn around times and frustration there of. I'll leave that at that.

Everyone has their own way of doing things but I pick a torque setting for action bolts and stick with it. Your rifle recipe lists Surgeon action and unless they have started making the RSR/RLR again, your scope mount and recoil lug are integral so no issues possible there. I know every barrel maker makes a dud every once in a while, but it shot good initially, so probably not there. RG does a good bedding job (it's prep work and tedious bit not hard) so probably not there. Bottom metal may give issues but mainly in feeding and OAL, not extreme accuracy problems. The scope is a definite maybe but you can test that easily. Since all we can do here is make educated guesses, knowing your rifle recipe and it shot well I initially, then something changed later. I used the word slathered when I mentioned copper fouling and I suspect that is where your problem lies. I don't know, but I suspect it. A proper copper cleaner is must on my shelves.

If you have already taken it to another gunsmith it's in his hands, so to speak, now. I hope it gets sorted out soon.

Betting the scope went south....

Yep swap the scope. Happens all the time.

Not being right there to look at the rifle, I think you answered your question right there. As others have stated, neither of your choices remove copper. Others have chimed in and given great recommendations for copper removal.

I'd also take a hard look at the Zeiss scope. I've had more than one go belly up in the last few years. Your mileage may vary.

Best of luck!

Thank you. Did a lot of cleaning today. Considerable amount of blue color on patches so hopefully have one problem out of the way.

Decreased and retourqued. Will be removing 36 mm rings soon and go back to my 30 mm rings to try a zeiss diavari 4-16x50 for the different scope test.

The last 300 win mag LR gun I had built was finished by an AMU armorer. Remington 40x solid bottom, Kreiger barrel, Mcmillan A-5 stock with a custom aluminum bedding block.. All I ever shot out of it was 210 bergers and a LOT of VV 160. Heavy bullets and a large powder charge will eat a throat out PDQ especially at 25 rds per match in 15-20 minute time frame. I sold it with 1800 + rounds down range and it was still a 1000 yard 1/2 MOA machine after all that.... Bet it's the scope or bedding.

Scope or mounts.

For copper removal clean the powder out first then use wipe out, squirt it in the barrel and leave overnight. Patch bore in the morning and you're done.

Copper fouling isn't causing this though.

Ballistol isn't really a solvent, and certainly not for copper. I believe its main ingredient is mineral oil. It's popular in black powder circles, but there are better products for modern arms.

As others have noted, swapping scopes is an easy and fairly conclusive test of the scope in question. And it's true, even high dollar stuff can puke.

Paul

I've used lots of cleaners kroil works for me

Scope or loose fastener. Guessing it's the scope.

For copper fouling, the best I've used has been Montana Extreme Copper Killer. You can leave it in the bore for long periods of time. Use in well ventilated area though, as the smell is pungent.

If your positive it's not fouled really bad then my guess could be a combination of a little throat wear and barrel speeding up, most will after about 100 rounds some take more than others depending on the interior finish and some speed up more than others. My suggestion is have a dummy round made up to know how far your off the lands so you have something to reference to when stuff like this happens. I would check about every 100 rounds some wear more than others.

From my tests the barrel has sped up. Plan to shoot some different hand loads to see what it currently likes the most. Thanks for your input.

Some good advice given here. One thing not mentioned, and maybe it doesn't apply, but how many rounds were you firing at a sitting? In other words how hot were you running the barrel? From what you have said I'm assuming you didn't abuse the barrel by firing too many rounds at a time and over heating it. If it was me I think I would be checking the scope first.

JIm

I'm going to take a different tack and postulate that the 300 WM has made you develop a flinch over time!








JK. My bet is on a broken scope, too.

I want to thank everyone for their input. Happy to report followed most of the suggestions. My rifle is back to touching holes (3 shot groups at 100 yards). What seemed to change things the most was switching from RL22 to H1000 and Decreasing the overall length of the cartridge. Thanks!