Noveske 6ARC throat question

Seems I backed into this same info, but glad to hear this is normal.

That’s what I get for loading without a case gauge. Thats being rectified next week.

I did order 300ct 80s. I may run these side by side and see how they hang out to maybe 750 and what felt recoil is like while unstable. Spotting 105s at 200 was hit or miss off a light schmedium. (1-8 NX8 that day) Has a touch more pop than a 77gr 5.56, so I’m gonna have to get my ass to work building quick structure …

Thank you. I really appreciate the help.

Chris

Edit:

Builds initial setuo seems fairly balanced. I was concerned this 3.5-15 F1 was going to be too heavy but it seems it’s going to handle well, even with the heavy can out front. (Really would I like a lighter , shorter can with Surefire hub, maybe a B&T Ti). Had to pick up a 10mm riser for the red dot. Will zero and hopefully get dope to 600 this Sunday.

This throat is pissing me off. 105s at 1.720” to ogive are fine. 95SMKs at 1.675” won’t chamber without jamming the bolt out of battery requiring a motor to eject it. It’s pulling bullets occasions as well.

Edit: been doing some testing and the virgin Nosler brass dummy’s stick. If I small base size them, they load and eject fine. Oddly enough, the dimensions seem good, and are way under a fired case in OAL to case mouth, and they’re .010” under fired headspace and belt line. Fucking strange… but it’s repeatable so there is something to this.


Case gauge will be here in a couple days, but this shit is frustrating and I’m running out of time to have my shit ready for the event Oct18.


As far as shooting:


105 shot fine. Groups improved over the course of three groups, starting around 1.5 MOA and dropping to under MOA, though in fairness the smallest group was only three shots as I was running out of rounds and needed 600 yard dope.

The four 95SMK I got to shoot went into .77 MOA, so about .8 MOA.

Hits on steel we’re clearly audible to 500, 600 I couldn’t hear but could see impact splash.

I am seriously thinking about throating this thing out about .050” just to be able to mag length and not jam the bullets. At least some bullets besides 80s.

Wade said:

I wouldn't be scared of hurting anything by throating it out if done properly. We've shot all variants of factory Hornady in +.050 and +.100 throat 6 arc chambers and they have all shot very well, just as they have with the saami throat.

Click to expand...

Thank you.

That’s kind of what I was thinking. That said the 105s seem like they’re going to work at 2.20” COAL. Funny , they mirror my 77gr Mk12 DOPE to 600 yards to within .25 MOA, at least so far. That is really convenient from a holds under pressure situation and they’re $.12 - $.24 less per bullet than anything else in the 80-107 weight. If I end up pushing out past maybe 750 yards I might need some more space for powder though.

I’m going to try 105s BTHP again, 105 Aeromatch, 95 SMKs and 80 ELD-VTs Sunday. If I can get one that feeds 100% reliably I’m going to run with it the 18th and take my chances.

Accuracy is there . Issue is I’m trying to figure out if it’s short stroking every few rounds or if it’s fast bolt speed. Ejection pattern shows low gas with 18 clicks on superlative arms. Cases land at 5 o’clock but fired cases are filthy and it’s missing the case head and grabbing the case half way up the body about every 3-4 rounds. Could also be these Norma cases, as I’m having to FL size virgin cases to get them to load.

The joys of sorting a new~ish rifle with no time to do it…..

I thought I had this sorted last Sunday. Went through 50 or so rounds. Bolt held open fine. Rounds loaded fine. Ejection at 4 o’clock. At the house before the range dropping the bolt to load a round allowed me to easily eject a round. Not sure I tried that with one that got chambered post firing BUT…

Yesterday I shot a DMR Run and Gun with the rifle. Loaded and shot fine, however every stage (6 of 6) I had to mortar the last round out of the rifle. Four of the six had a bullet stuck in the rifling, spilling powder all over the receiver. I was carrying a collapsible cleaning rod (I do so I don’t get DNFd if I break an extractor, etc) and had to rod the bullet out. I almost left it in the truck and was glad I didn’t or my day would have ended 8 minutes into a 2 hour run.

These 105s are loaded to 2.20 COAL, with a taper crimp and still the force of loading them during normal cycling is causing the bullet to slide forward and jam.

I am going to give the Nosler brass one more go. I’m going to buy a FL bushing die to try to get the NT to a point that the bullets won’t slip. If that doesn’t work I’m going to have to abandon this shit, which sucks because it’s half he price of Hornaday or starline. Guess I know why now. Seems like this brass was made for bolt actions.

I know the title is what it is, but I’m implying this has anything to do with the rifle barrel. It performed great but this brass seems to be the weak link.

Alright. I took a step back last night and did some re-measuring. I’m allowing a .010” HS difference due to the brass used for the case gauge, so add .010” length if using a fired case for he gauge.

The Nosler brass is an issue until FL sized BUT I don’t think it’s the only problem I had…. Long, but if you’re going to buy one of these Noveske barrel you’ll want to follow along. Mine could be an outlier, but it might not be.

I have a Stoney point case gauge (not fired from my rifle, just off the shelf) and before the practice session the Sunday before the match I measured the COAL at 2.120” . I didn’t believe this, as rounds loaded to 2.20” COAL cycled fine by hand so I practiced with the 2.20” 105s and they ran fine. I think what I neglected to do was try to eject a live round that had been loaded automatically from the rifle cycling. You can see the results in the post above.

Last night I re-measured and I got the same measurements. 2.120” so I Sharpie’d a bullet and sent it home from a fully detected charging handle. Bullet was set back .010” and had a fairly decent ring, though I suspect this was from extraction. Yes, I had to mortar it.



I proceeded to seat the bullet down to a COAL if 2.105” and it cycled fine but damn this thing is deep in the case.



I re-created this test three times and the results were the same, I at this point I am convinced this throat is too short for the Hornaday 105 BTHP.


I’m taking the rifle up to my buddy who builds all my shit and ask Tim to throat it so a 105BTHP is 030” off the lands loaded to a COAL of 2.250”. That should open up the case for some powder and hopefully allow me some wiggle room. Also buying a bushing neck due to tighten up the neck tension.