LVR and pressure

[Newmexican]

Still learning the mysterious ways of the 6mm ARC, but was a bit surprised by the apparent pressure signs I got recently when shooting handloads out of the Savage Axis II. Using once-fired cases with necks uniformed and full-length sized in Hornady dies, I loaded LVR over CCI 400 primers with the Berger 95-grain VLD to a COAL of 2.250".  I started with 30 grains, with no signs of pressure. With 30.5 grains of LVR, I noticed very slightly increased bolt lift and some primer cratering. Accuracy was so-so, with three-shot groups at just under one inch. I moved up to the 31-grain loads and the first round gave what I interpret was as close to a pierced primer as I care to get, with the primer appearing to have been struck with a small, round punch and enough gas released to darken the hole. Needless to say, I took the rest of those loads home to tear down. Before leaving, I fired a half box of the Hornady 108-grain ELD Match and put four into about .4 inch with a fifth a quarter inch away, but the wind was quartering from behind at about 15 mph and I confess I am still getting used to the rifle. 
In the photo, the two cases on the left were loaded with 30.5 grains, the one on the right with 31. I arrived at the 31-grain load by extrapolating (I know, bad me) from the Hornady bolt gun data showing a maximum of 31.4 grains for their 100-grain Interlock BTSP hunting bullet and 30.8 grains max for their 103-105-grain Match bullets. 
By the way, the two cases at left were from factory loads initially fired from an AR, and I scrounged them up; hence the roughed up rims.
Anyway, I would like to hear from others who might be running the Berger 95s with LVR.

[Dino11]

The first mistake you made was using CCI 400's on a bolt gun load. You should be using CCI 450's. The 400's are just to soft for the pressure the bolt gun load produces.

I have no experience with the Berger 95's but have used the 100 Interlocks. The Interlocks in my opinion are not very accurate but make a nice plinking round, they are accurate enough to get 1 to 1.5 MOA. But they are cheap enough to keep some on the shelf for shooting steel.

[StoneHendge]

It's not that the 400's are soft - the cup is thinner. The chart can be found here https://www.accurateshooter.com/technica...-analysis/

[Dino11]

It's not that the 400's are soft - the cup is thinner. The chart can be found here https://www.accurateshooter.com/technica...-analysis/

Yes I was aware of that... The thinner cup makes it soft compared to the 450's.

[grayfox]

I shoot 95 berger's. And echo Dino on not using the 400.
What MV were you seeing, the savage, that's an 18" barrel right?
But another couple things...
1 is your coal. Even for the vld 2.250 may be too far into the lands, asking for pressure spikes when the bullet cannot move enough at the start; did you check available oal with something like the hornady oal gauge? Plan on 30 thou as a min jump for the 6Arc.
2d is the 31 could definitely be too hot more than likely for your barrel. I'm settling in around 30 grs with my 22" uintah bolt gun.

Like its bigger brother the grendel, 6Arc is not a hot rod.

Try working up using cci41's, 450's or fed 205AR's. Also for the ladder use 1% case volume increments, like 0.3 gr - a 0.5 or 1.0 delta is too rough to be able to get good info on finding a node.

[Newmexican]

Gentlemen, I appreciate your replies. I will try the 450s -- or BR4s.
As to COAL, I confess to not having an OAL gauge. I just seated until the bolt closed easily. Will remedy this immediately.
The Axis II has a 22-inch barrel.

[grayfox]

ok, yeah, do some fiddling and "find" the oal where it hits the lands, then measure and back down a few 0.001's to get some seating.
From the BC's of the classic hunter and vld's (and I could be off here), but I didn't see a lot of BC difference, which tells me their shape is more alike than different... and my 95 berger classics touch lands at 2.205-ish. So I seat them anywhere 2.160-2.180 (still working on the best oal).
Now the Sierra 95 TMK's seat out to 2.318 so I have lots of room to seat them out to 2.260-2.280.

There's a hornady lock-n-load length gauge (need to buy the various modified cases too), that's what I use. Everything was on Amazon (for lots of calibers btw) except for the 6 Arc modified case... I found that at Copper Creek, or may need to google it.

[r.tenorio671]

    ....The Berger 95 Classic Hunter (CH) has a "Hunter HYBRID " ogive and is 1.069" long.  The 95 VLD has a "secant" ogive and is 1.113" long.  In MY barrel the CH "touch point" measured at 1.730" for a corresponding 2.197" COAL.  The VLD "touch point" measured at 1.726" for a corresponding 2.328" COAL.  The attached images show the differences in COAL for various bullets (Bgr 95 VLD & CH are 2nd & 3rd from left)  for a similar "touch point" of their ogives as indicated by the thicker line bisecting the high point of the ogive.

---

        ...the images of the Berger 95 CH and VLD  in my Sheridan Engineering case gauge, which is cut with a chamber reamer, showing how the different ogive types and OAL of the bullet will interface with the chamber and affect the loaded cartridges COAL.  YMMV

[grayfox]

Looks like there is some difference, ok.
OP yours will probably be similar depending of course on the differences in Sinclair's reamer and Savage's.
You will want some jump to lands for your pills.
Still a good idea for you to get some system for measuring your own oal's in your barrels.

[Bill]

Newmexican I always er on the side of caution with seating depth especially with long for calibre projectiles.

I reckon you probably should have started in the 2.180-2.200 range. Shorter 65-70gr bullets can handle a bit of jam if you dont mind seating them out.

As other have mentioned upgrade ya primer to a harder thick cup, I'm a big fan of the Rem 7.5s thou the CCI 450 can be a good option.

[r.tenorio671]

Gentlemen, I appreciate your replies. I will try the 450s -- or BR4s.
As to COAL, I confess to not having an OAL gauge. I just seated until the bolt closed easily. Will remedy this immediately.
The Axis II has a 22-inch barrel.

FWIW, both Eric Cortina and Primal Rights both have videos out that illustrate methods of finding the lands with bolt action rifles. 


https://forums.gunhive.com/topic/2324/me...h-to-lands


https://www.youtube.com/watch?v=a7vjgEgnhHk

[Kra]

Hey Grey quick side question, I’ll likely be buying the unitah 6arc 22”I have the .223 version was wondering how you like the 6 offering? Good info on the jump thank you for that.


I shoot 95 berger's. And echo Dino on not using the 400.
What MV were you seeing, the savage, that's an 18" barrel right?
But another couple things...
1 is your coal.  Even for the vld 2.250 may be too far into the lands, asking for pressure spikes when the bullet cannot move enough at the start; did you check available oal with something like the hornady oal gauge?  Plan on 30 thou as a min jump for the 6Arc.
2d is the 31 could definitely be too hot more than likely for your barrel.  I'm settling in around 30 grs with my 22" uintah bolt gun. 

Like its bigger brother the grendel, 6Arc is not a hot rod.

Try working up using cci41's, 450's or fed 205AR's.  Also for the ladder use 1% case volume increments, like 0.3 gr - a 0.5 or 1.0 delta is too rough to be able to get good info on finding a node.

[grayfox]

I like the uintah, a lot. It's a very stable and accurate barrel-upper setup.
At the time about the only bolt action 6 Arc I could find, esp wanting something longer than 18"...
I like savages too, but wouldn't trade my 22-U for an Axis ever.

[Newmexican]

Have the Hornady OAL gauge and modified case en route.
Grayfox, that Uintah bolt action upper is sweet. I wouldn't trade one for two Axis rifles, but the Axis was all I could afford. I may end up with Howa envy though ...

[grayfox]

You should be able to get that axis to shoot, most of their barrels are ok as far as that goes.
I typically run some JB bore paste thru them upon receipt to smooth out the insides of the barrel.
It will probably be a bit more finicky however, for bullet/powder combo's.

[Newmexican]

I did run some JB bore paste through the barrel prior to shooting it. The Axis has a pretty homely action, but I have always had good luck with Savage barrels -- and the rifle was available and affordable. Wish Hornady would get around to producing brass for handloaders.

[Newmexican]

Follow up: I used my new Hornady OAL gauge and modified case with the Berger 95 VLD, and it touched the lands at 2.188 No wonder. Will try again seated to OAL of 2.170 or so.

[Bill]

Id let it have a little more jump first like 2.150 if you cant find an accurate load then bump it out 5 thou or so. You want speed without pressure

[grayfox]

That OAL ismore like I was thinking at first, it definitely pays to measure.
I too would seat back towards 2.150 if you can, watch for load compression.

[r.tenorio671]

Follow up: I  used my new Hornady OAL gauge and modified case with the Berger 95 VLD, and it touched the lands at 2.188 No wonder. Will try again seated to OAL of 2.170 or so.

...FWIW,  I seated them with a COAL that would fit within the magazine (gasser) and it equated to an approximately 0.0730" jump in my chamber.   

A LVR load of 29.1 gave a 3-shot group of approximately 10/16" edge-to-edge, when testing for pressure.  I wasn't focusing on accuracy, just getting it centered across optical sensors of my old Chrony Beta.  YMMV.