Home Forums Hunting & Shooting Custom Rifles & Wildcats Accuracy question

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.