Browning X-Bolt loads not coming together

[grry10]

I working on developing a 300 Win Mag 180 grain AB load for a Browning X-Bolt, with factory synthetic stock and factory light contour fluted barrel. I've exhausted attempts with RL-22 (best was 1.5" @ 100 yds), IMR-7828SSC and am working with IMR-4350 now. It has not showing a lot promise yet with 71.5 and 72.0 grains. I've been using WLRM primers, Hornady brass and bullets seated to 3.475" COL for testing. Factory Hornady 180s grouped in the range of 2.25"-2.50" @ 100 yds, which is why we're trying to get a handload to shoot better.

I would like to get some feedback from someone who has loading experience for a Browning X-Bolt in 300 Winchester Magnum.

 

[Charlie-NY]

Just my opinion but virtually no modern factory rifle should shoot 2.5" groups at 100yds with factory ammo. I'd be looking closely at the scope and mounting system. Barring any issues there I'd be on the phone with Browning. A $300 low end rifle normally shoots better than that.

FWIW - My Browning X in 6.5 Creed (all factory except the trigger) easily shoots under .5moa.

 

[grry10]

At this time we don't have access to a range longer than 100 yards, so shooting a ladder is out of the question. All screws including action, mount and rings, were checked and torqued and the scope is a known good one.

 

[Tjay]

I would try seating the bullets shorter. AB like a running start.

 

[Nimrod84]

Grry10,

No experience with your exact setup, so I'm sorry but I'm not the guy you requested... I would 2nd what Charile wrote about contacting Browning, something sounds off about the rifle. Might be a cockeyed bolt or chamber, maybe a nick on the muzzle, overly aggressive cleaning with abrasives that rounded the rifling, something... I have a Kimber Classic in 30-06, it had a gouge in the chamber that was giving me accuracy problems; I couldn't see it, but I could feel it and on extraction the brass was marked.

Only thing that jumps out in your load data is the OVAL. Like Tjay, I'm not sure how far from the lands you are seating, but I've always end up 0.04-0.07 off the lands with the Accubonds. I've shot hundreds of them in multiple calibers and that seems to be about ideal for them, other shoots have noted that they sometimes work well about 0.1" off the lands. If you have time, a good read on jumping bullets is at: https://precisionrifleblog.com/2020/03/ ... velopment/

You didn't mention what the groups look like. Advice I received years ago that has served me very well is: "The shape of the group tells all. If the groups is a large equilateral triangle, seat the bullets out a 1/4 turn on the die and repeat until the group shrinks. If the group is 2 together with the 3rd out there, seat the bullet deeper in the same manner, a 1/4 turn at a time and the group will shrink."

 

[mjcmichigan]

Here’s a 300WM 180gn AB iMR4350 load I used on bear. The AB liked jump. OAL was 3.329” 68.3gn. MV was 3060 on the chrono.

I’ve had lots of good luck with Hornady factory ammo shooting Sub MOA in many calibers.

I know you checked scope, mounts and rings. How’s the barrel floated. Can you run a dollar between the barrel and stock all the way to the receiver.

I have a Savage 3006 that the front bedding lug works itself loose time to time and my 3/8” groups get up to 2”.

If that’s not it, call browning or talk to your gun smitty. Xbolt should be sub MOA with factory ammo.


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[Blkram]

And check the barrel muzzle crown, this can bean overlooked problem for accuracy, even on new rifles.

 

[JD338]

I have to agree with the others, something is amiss here.
What scope and ring/mount set up do you have? Too big a scope on the wrong mounting system can cause a scope failure.
The RL22 load (75.0 grs) has been a proven accuracy load for me shooting well under MOA in 3 different rifles and there are several others that have reported similar results with that load.
This makes me wonder about copper fouling.
Have you done a deep cleaning with Sweets 7.62 or something similar? I'd give that a try to make absolutely sure you have every last bit of copper out and then try the above load.

JD338

 

[diverdown]

Just a thought. Before I went any further I would try another bullet. I've heard a few of our members say they couldn't get an AccuBond to shoot. I had problems trying to get them to shoot in my M700 in .338RUM. It does happen.

 

[gbflyer]

There is a 190gr. Federal Gold Medal Match load available for your .300WM. It is not hunting ammo. If you can access a box of it, try it. If it won’t produce acceptable hunting accuracy, there is something wrong with the rifle. If it does produce acceptable accuracy, then the rifle has potential and there is a hunting load out there somewhere that will work. You might shoot the barrel out before you find it though. [emoji1]. For me, 1.25 MOA or maybe a tad larger even with three shots is acceptable especially out of a factory lightweight. But more importantly is the cold bore shot going where it’s supposed to? That’s the big one, to me.

Good luck.

 

[lhsako]

I have to agree with the others, something is amiss here.
What scope and ring/mount set up do you have? Too big a scope on the wrong mounting system can cause a scope failure.
The RL22 load (75.0 grs) has been a proven accuracy load for me shooting well under MOA in 3 different rifles and there are several others that have reported similar results with that load.
This makes me wonder about copper fouling.
Have you done a deep cleaning with Sweets 7.62 or something similar? I'd give that a try to make absolutely sure you have every last bit of copper out and then try the above load.

JD338

>>> 75 Grains RL22 sub inch in my .300WM Sako w/ 180 tips. All great advice posted here from everyone. Investigate and eliminate.

 

[baltz526]

Try a 165gr Partition and a 180gr protected point Partition. Light barrels are not exceptional for long sleek bullets. Both will have plenty of good impact results, at the ranges a light rifle is good for.