Pre-fit barrel alignment
- By memilanuk
- Bolt Action Rifles
- 52 Replies
You and me both
Got the action, took it home, screwed one barrel on, with scope A. Put it in the bench vise, no stock. Still pointed the same damn place - ~5 mils right. Took that scope off, put on scope B (FWIW, both had been mechanically centered at the start of the session). Same damn thing. Took that scope off, put the other barrel on with scope A. Same. Scope B. Same.
So... not saying that the original stock bedding doesn't have some areas that need addressed, but I think that's a separate issue and not a part of whatever fuckery is going on here.
Said 'fuck it' and put the first barrel (NSS/Shilen nutted .223 Rem, 26" med. Palma) and scope A (Burris XTRiii 5.5-30x) back on, and dropped it in the KRG Bravo. Took it to the range and... of course, this time of year, it's about 50/50 whether I can even *see* all the way to the 100yd targets. Had to go over to the 50yd pistol/carbine bay to bore sight it. Ended up... almost f'ing centered for windage, maybe 1 mil off by the time I got it on paper @ 100 when the high fog/low clouds cleared a little. Gun shot... okay, but then again the conditions were far from ideal.
Around about the same time, I got a lightly used Proof CF 20" .308 Win shouldered pre-fit. Boresighter/collimator seemed to put it close to the same POA as the NSS/Shilen barrel. Cleaned the snot out of it, grabbed a box of factory Berger 185 OTM, and got up to the range (another day). Still chilly, but better visibility. When I got it on paper, it was pretty much *exactly* centered. But...
Something just seems 'off' about that scope. Between the two sessions (30rds for the .223, 20 for the .308) there were multiple times where I'd shoot a group, look at the grid on target or use the reticle and decide I needed to come over X amount, and up Y amount. And every time, the corrections would way over shoot where I was aiming for.
Part of me want to put the .223 barrel back on, and just box-test the fuck out of this scope - and the Bushnell XRSii 4.5-30x, just for comparison. Hell, even drag out one of my old NF 12-42x scopes for a sanity check. The other part... thinks I should probably put the 6.5CM barrel back on, and see where it *actually* prints on paper with the Bushnell XRSii, vs. where it prints with the Burris XTRiii. Then box test it with *that*.
That's where things went off the rails to begin with: the Burris XTRiii on the Proof 6.5CM barrel not holding POA, not tracking as expected, and generally acting like it'd ran into the inside of the tube. *That* was why I originally tore the whole f'ing gun apart, and as a result of taking the scope out of the rings, that was why I stuck the boresighter/collimator in there to check.
At this point I don't *think* it's anything to do with the action. I don't think the stock / bedding was the primary culprit, though I'm guessing the bedding around the one nut might have caused some issues with the other nut. I also don't think the barrels or the nuts themselves are the root cause here either - the one shouldered pre-fit that I borrowed earlier 'pointed' the same place as the two nutted barrels, and so far the shouldered Proof barrel I have now 'prints' the same place as the NSS/Shilen nutted barrel.
I'm leaning towards it being a conspiracy between that damn Burris scope, and the boresighter. The one acted all fucky, which led me to tear down things, and the other - for some reason - has started pointing off to one side or the other.
So... no definitive answers yet, as far as I can tell. If someone else can suss out something from the above, I'm all ears.
