I'm dying right now....my new bartlein 2b spun up on a push feed winchester in 300win is being difficult.

Headspace is on the minimum side, dialed in to two tenths on the chamber and tennon with no issues threading or reaming. I took an inch off the shank and reamed the whole way home.

The gun is well bedded, 2# trigger and wears a rail landed with devcon after media blasting it to ensure it doesn't move.

I've been through two scopes that work well on other rigs and this thing is a 6 inch gun more often than a 2 inch.

I've indicated the action from the scope, no movement. Bedding to action, no movement.

The barrel doesn't look bad when I scope it, but it does have a tight spot about 8" from the muzzle when I shove a tight patch through it.

I'm a bit over 100 rounds of berger 200.20x, 208 eldm, long range accubond, and now going to try some classic sierras and rdfs. I've tried h1000 and h4831 and neither powder nor bullet makes any difference....it blindly sucks.

Action and ring screws have been dyed to ensure zero contact. Latest scope is a lrhs in burris tactical xtr rings.

I'm running out of stuff to chase down beyond the tube.

The worn factory tube will shoot 6x better than the new one.

I fired another, lighter 300 on the same target at the same time and rip a clover.....then this thing sprays pills at random.

Labradar shows reasonable speeds and good spreads on some loads. I've taken the 200's from 2600 clear to 2900 and nothing is neat. Seating have been varied from a kiss to 200 off.

I'm stumped....and about to throw this tube in the river and spin up another one of the cheap proofs I have been having luck with.

Any ideas?

And....I started with a deep recessed crown and have since peeled it back .5" and cut a sharp shallow one....no effect.

Couple of things that you may have already checked, but...
Front scope base screw(s) long enough to touch the barrel shank? Thus can make a screw seem tight, but still allow a tiny amount of movement.

Bolt handle contacting the stock? This can make strange things happen, too.

Bolt nose contacting the barrel? You said the headspace is tight, so I'd check this. I had a Savage PTA rebarreled with "zero" clearance between the bolt nose and the face of the barrel. Shotgun patterns. Backed the barrel out, easy to do with the barrel nut, torqued it back down with about a thou and a half clearance. Groups shrunk to 1/2 MOA or less, and were consistent, no more weird flyers.

On the plus side, you make me feel real good about my gunsmithing abilities.

Hmm.. Cheap proof barrels …

Barrels are throw away, but nothing is cheap these days.
I always scope and slug (check and measure bore consistency) before I start machining so I can send it back if I have too…


Like the guy said earlier - look hard at your scope mounting gear 2 or 3 times before moving to tear things apart…
If you are a smith and know how to slug & Lap a bore (given you chamber it)… that would be your next step IMHO.

Or start over with a new barrel… ouch.

If the new barrel really was that bad, Bartlein might still swap it out after you threaded & chamber it… but it will probably get a turned up eyebrow…

Without having the rifle in hand, these deals are tough to diagnose. On the model 70's, here's a couple things I'd check:

-Make darn sure the bolt nose isn't contacting the barrel. If it's close, it can touch when the back end up the bolt moves up when it's cocked. .007-.010 would be what I'd want back there. If it's a non coned bolt 70, make sure the counterbore dimension has adequate clearance as well.

- If it's a center action screw Model 70, loosen the action screws, pull the barrelled action out and put it back in with just the f-r screws. Then very lightly just snug the middle screw enough so it doesn't fall out.

- If it's bedded, make darn sure there's clearance between the bedding and back receiver vertical ledge ahead of the tang and behind the rear cross pin hole. If it's touching there, you basically have two recoil lugs...not good. Make sure the lug isn't tight against the sides or bottom. The only contact should be at the rear.

If all this seems right, I'd screw the original barrel back on as a 'control'. -Al

Not familiar with the Win70 box magazine. However, if it is like the Rem 700, have you checked to make sure it is not binding up and is floating inside?

Bolt nose clearance is .012" measured on crushed solder, .01" when I measured it on assembly. There's zero bind in the mag well. I did not relieve the rear vertical, but I built another m70 the week before and bedded it exactly the same and it shoots into the .3's......but I will sure open it up at this point. The screws have been measured and dyekemed for verification and they are not the issue.

I've only seen a gun shoot this bad with optics issues. I will try the third scope today.

Thats funny

Lap that tight spot out of the barrel. Check the amount of constriction with a lead slug beforehand. If it still doesn't shoot, pull the barrel, take it to the nearest, good-sized, body of water and, with you eyes closed, throw it as far as you can into the lake. Wait until the ripples have subsided before you open your eyes. You don't want to be tempted to try and retrieve the barrel. GD

Sitting at the range right now. I shot a group with a different scope and 200ab's with 4831 that wasn't much different than the original scope. I put the original scope on my steel proof 21" 300 and ripped a tiny 5 shot....scope isn't the issue.

Cut to 2:09

Same scope....two rifles.

I just spoke to bartlein and they told me a 10 twist won't stabilize a 200gr plus tube. I shot the tiny group above and several like it with another 10 twist 300....weird. The bart did shoot 175rdf well. So apparently a bartlein 10 twist will not spin the same as proof and lilja in the big 30's.

I'm not pleased with the results on the heavies, but at least it will shoot smaller pills. Kills the design intent on this one though. The 21" gun will beat it at everything.

That's unusual. I always thought the 10 twist was standard on pretty much all 30 calibers. Unusual.

kwg

I have a 10 twist Bartlein on one of my 300 win mags and it wouldn't shoot 208 gr match bullets worth a hoot. I wish I'd of seen this thread before I tried 4 different powders and countless different COAL. The one thing that I noticed was, the shorter the COAL the better it shot. I was scared to load Magnum powder short, it was so compressed.

Simply measure the ACTUAL RPM of your spout. Sometimes,The Billing,don't match The Goods. Hint................

Easy enough to see if Bartlein is right. Load up some 165s and see if they will group. Also, I'm sure you already addressed this but did you deburr your crown after cutting the recess?

I'm slow to poke the cart,in front of the horse. Hint.

Billed RPM,ain't ACTUAL RPM and such things are easily resolved in seconds. Simply punch bore with cleaning rod and denote them findings,because NOTHING fhuqking else matters. With that KNOWN quantity,suitable projectiles are easily extrapolated,in relative viability. Hint.

For conversation a TRUE 10" RPM,is a TRUE 10" RPM,no matter the Maker and assuming a static RPM,as opposed to an increasing/gain twist. I've shot bazillions of 208's in 10",11",fractions of 11" and 12" RPM spouts,in a multitude of chamberings,at Low Tide. A 10" at said velocity(WORST case 300 Winny at 2600fps),is welllllllll beyond HAPPY,as stability goes. Hint.



This schit is EASY if you allow it to be and much can be KNOWN,welllllllll before the first shot. Hint.

Just saying..............

I had made the suggestion to check the twist with a new brush in another thread about this. -Al

Yup, always start with the easy stuff first...