Criterion 260 "Match" COAL question

[obiwannabe]

I recently bought a Criterion 260 Rem "Match" barrel form Jim at NSS. The "Match" version has additional freebore for the 140gr bullets--0.160" vs 0.118" for the standard reamer.

When I got the barrel the first thing I did was check the max seating depth with the Hornady 140gr SST I'm loading. I was surprised to see that the bullet jammed at a COAL of 2.830" just at the bottom edge of the cannelure. My Savage 10 (centerfeed, blind mag) box will allow 2.960" which is great, but not if I can't use all that length.

I loaded a 25 round ladder of 7828ssc at a COAL of 2.810". The Hodgdon manual lists a compressed max load of 47gr. I started at 43gr which was already compressed so i only went as high as 44gr. I started breaking in while putting 5-shot groups on paper. Accuracy was okay but nothing special with all the groups in the 1.5"-2" range.

I really thought something wasn't right with the barrel so I cast the chamber and noticed that there were two lands on the cast that seemed to extend down into the freebore. I thought perhaps the throat was off center and causing the bullet to jam early.

I contacted Jim and he put me in touch with Steve Dahlke at Criterion. I talked to Steve on the phone and explained the issue. He had me send in the barrel for inspection.

Today I heard back from Josh at Criterion that there is no problem with the barrel. They repeated my measurements with a Stoney Point gauge and confirmed a max COAL of 2.830" with the bullet I sent them.

So here is my question for anyone out there with a Criterion 260 barrel (standard or "match") loading 140gr bullets--does that sound reasonable to you?

I really thought that 0.160" of freebore would at least get me to mag length. If this is true then the standard chamber with 0.118" freebore would have a max COAL of just 2.788". At that length the SST's cannelure is fully INSIDE the case neck. I'm still not convinced that this is normal.

Anyone loading the 140gr SST in a Criterion barrel--match or otherwise? What COAL are you getting?

[jhelmuth]

I'm loading 142gr SMKs at 2.875 COAL CBI .260 Match SS. Using RL-17 and my groupings are 0.26 MOA.... (Lapua brass and CCI BR primers)

http://www.savageshooters.com/showthread.php?39054-New-260-Rem-Savage-Gun-porn

[obiwannabe]

Okay. How far off the lands are you at 2.875"? The SMK's have a tangent ogive too which I would think would make them seat a bit short(er).

[Wildboarem]

I don't have my loading book in front of me. I believe my col with 140gr Barnes burners and amax's is 2.875 sitting .018 off the lands. This is a standard small shank CBI .260. Something sounds off on that chambering.
I would get there response in writing. Were they able to explain the anomaly of what you found in the chamber cast?

[obiwannabe]

They've said nothing. They've confirmed my measurement and seem to be assuming that it's normal.

[trailrider121]

I have a Criterion 260 .160" match chamber. I don't have any 140 SST to measure. If you want to send me some 140 SST, I would be happy to check for you. Did they confirm it was a match .160" freebore?

My 260 barrel / Touching lands:

123 scenars at 2.894" COAL
130 VLD Hunting @ 2.940" COAL
140 Hybrids @ 2.970" COAL

[obiwannabe]

If you want to send me some 140 SST, I would be happy to check for you. Did they confirm it was a match .160" freebore?

I appreciate that and I may take you up on it. I just sent another email asking if they could check a different 260 match chamber with the bullet I sent.

My chamber cast confirms the 0.160" freebore. It's just not consistent all the way around the throat.

Here is one side of the cast showing what looks to me like a normal land and leade angle.http://i1291.photobucket.com/albums/b548/tuppertn/20141028_064813_zps5a6df4d8.jpg (http://s1291.photobucket.com/user/tuppertn/media/20141028_064813_zps5a6df4d8.jpg.html)

The phone camera pic is poor quality but, here is the area of concern on the opposite side of the cast. I know we're talking about maybe 0.001-0.002" at most but the land right next to this one looks about the same. I think between the two of them they are stopping the bullet both early and off center. Is that reasonable to think or am I making something of nothing?
http://i1291.photobucket.com/albums/b548/tuppertn/20141028_064803_zpsd22466b7.jpg (http://s1291.photobucket.com/user/tuppertn/media/20141028_064803_zpsd22466b7.jpg.html)

[obiwannabe]

Just got off the phone with Josh at Criterion. They tested that barrel with a couple other bullets. The 140gr Berger VLD Hunting seated out to 2.950" which sounds pretty typical to me. The 140gr SMK went out to 2.84x". So maybe it is something about the shape of the SST that makes it seat really short.

I'll be talking with them again tomorrow to decide what to do with it. Josh hinted that Steve had an explanation for what I'm seeing on the chamber cast.

Gotta say that both Josh and Steve have really been great from the CS standpoint. Sounds like they're willing to do whatever with the freebore to be able to load at the length I want.

[obiwannabe]

Just in case anyone is still reading and curious how this is working out...

I just talked to Steve Dalhke, the owner of CBI. The rifling marks in the freebore are normal and due to the difference between the bore diameter and the reamer's throat diameter. Criterion Barrels are bored to 0.2643"-0.2645". Their "Match" reamer has a throat diameter of 0.2641". That difference of a few tenths of a thousandth of an inch can show up in the freebore.

Turns out that the Hornady SST is just a short-seating bullet. It's advertised as a secant ogive but I can't tell that by looking at it. The nose is relatively short and the bearing surface relatively long so it seats consistently shorter than even a 142gr SMK. Having no other bullets on hand to compare it to I had no idea that was the case.

They're going to ream the throat closer to 0.265" for me and keep the 0.160" freebore. That will give a little extra seating room for my hunting loads without messing things up for any future loading I do with VLD's.

Again, hat's off to Steve and Criterion Barrels for unbelievable customer service. Even though there's nothing wrong with my barrel they're going way above and beyond to make me happy.

[trailrider121]

It's good to hear that Criterion is taking care of their customers, and thanks for sharing.

[obiwannabe]

Got the barrel back a few days ago. Interestingly, with the same freebore and the new throat just 0.0009" larger than before, the SST's now seat out to 2.876". Hmmmm...

Anyway, I put 25rd ladders of H4831sc and H4350 through it this afternoon with 140g Berger Hunting VLD's seated 0.010" off the lands. Of the 10 groups, 7 of them were 0.6"-0.8". One would have been 0.24" if not for one shot falling outside the ragged hole. Also, I've never been able to shoot my best groups with a 9x hunting optic so there's some room to work with it.

All in all a bit of a rocky start but it seems to be ironed out now thanks to the folks at CBI.

[upSLIDEdown]

Never saw this until now, but yeah, a 'match' chamber is probably designed for a more 'match oriented' bullet, which the SST isn't. I would think it'd be based off of an a VLD, Hybrid, and/or SMK. Those are more the type bullets people wanting a 'match' chamber would be using. (This is coming from someone that shoots a 6.5CM as his main long range rig, and uses the 140 Hybrids to do so).

Sounds like you're getting her dialed in, regardless. Keep it up! :)

[obiwannabe]

Never saw this until now, but yeah, a 'match' chamber is probably designed for a more 'match oriented' bullet, which the SST isn't. I would think it'd be based off of an a VLD, Hybrid, and/or SMK.
Well, I never got the SST to yield good accuracy in the velocity range I'm looking for. I found a node down at 2620fps then it was just scatter until things started tightening up again just as I went over max. There's an upper node in there somewhere but it's over 2920fps.

[LongRange]

Just curious did you ever try a different primer or powder?
I ask because I had the same problem with the 140g match bullets and last Sunday I loaded a few rounds with Remington 9.5 primers and my groups tightened up big time. I was just about to give up on the 140s.

[obiwannabe]

Just curious did you ever try a different primer or powder?


Tried 7828ssc and H4831sc ladders in the upper half of the charge range. Fed 210 primers for both in Federal cases made from 308 brass turned for a final neck thickness of 0.015". I do have some BR-2's I could try.

[LongRange]

No doughnuts at the base of your neck? What was your neck tension? If I was you id ditch the 308 brass buy some 260 brass and definitely try a different primer...I was a huge fed primer fan for years but it seems like the fed primers ive tried over the last 1.5 -2 years have been very inconsistent. Ive switched to cci for the most part but have every other primer you can think of lol. I really dont care for remington primers but they sure tightened up the groups. I have a couple loads with H1000 and H4831 that are lasers but just under 2700fps they wont shoot to well in the wind. I just got and preped a box of nosler brass which should give me quite a bit more case capacity over the lapua so im going to go back to the H1000 and H4831 and see what happens, ill let you know.

[obiwannabe]

No doughnuts at the base of your neck? What was your neck tension?.
No doughnuts. I turn the necks down to the neck/shoulder junction before I form them. The finished case ends up turned ~1/16" onto the new shoulder. After fire forming I use a Redding S-type neck die with a .292" bushing for 0.002" tension.

[LongRange]

you are on top of all that then...id say start by trying the BR-2s and see it that helps at all if not maybe try some 4350 or RL-17...i prefer IMR4350 over H4350 as its a little easier to find and it gives me a few FPS more with the same charge weight in my riffle.

[obiwannabe]

The Berger 140gr Hunting VLD's are shooting so stinkin' good I've kinda lost my motivation with the SST's. :p

http://i1291.photobucket.com/albums/b548/tuppertn/20141121_105933_zpsb17d2bee.jpg (http://s1291.photobucket.com/user/tuppertn/media/20141121_105933_zpsb17d2bee.jpg.html)

[LongRange]

There you go!!!
Nice group...ive owned a few riffles that were very finicky and the worst one of all I still own. I cant tell you how many times I wanted to through it in the brush where I shoot and just leave it there lol..I think you found your load and bullet your riffle likes now just stick to it.