Short chamber? Varberger 7x57

JockStalk

Well-Known Member
Have had some challenges getting factory Geco rounds to chamber in my Varberger 7x57. After a bit of playing around (thanks to Andy at MorayOutfitters) seating the bullet 3.5 mm in from factory it started to chamber and extract OK without unacceptable overpressure.
Still well within spec, 72.5mm overall.
Slightly more of a kaboom, but its a soft shooting round and its really no big deal.
Anyone have similar Varberger experience?
The Geco's grouped well and took my first couple of roe with them yesterday, without major meat damage. 165gr did drop them quite quickly....
JS
 
Are you sure that the throat hasn't got a build up of crud in it from a possible history of shooting shorter bullets? 3.5 mm shorter than factory COAL sounds a bit much to have to go to clear the lands. If it is clean & you have a very short throated chamber(a bore soope inspection would confirm this), a session with a Hornady L&L gauge would give you a known length to work to.
I have a mate who religiously cleaned the bore but not the chamber - he suddenly tried some factory ammo & couldn't chamber it! - That was a hard crud build up in the chamber /throat. A thorough scrub out of the chamber sorted it for him.
If you can tell the difference in BOOM you must be getting higher pressure - do check for signs on your cases very carefully - you don't want to be repeatedly overpressuring your nice classy rifle!
 
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Thanks Yorric.
The chamber is clean - rifle hardly been used to be honest. I should have mentioned that I've used 140gr S&B without any problems at all.
Geco cases checked, (by a more expert eye than mine!) and no sign of overpressure - so confident pressure is safe. Modern rifle and before starting to adjust the standard Geco round is 2,370ft-lbs. So we should be within safe limits.
Its a strange one, because the S&B's are absolutely fine.
It just seems strange to me that one round will chamber perfectly and another just won't, until seat reduced.
And its my pride and joy - so definitely want to avoid damaging it. Don't even like getting it wet!
JS
 
It just seems strange to me that one round will chamber perfectly and another just won't, until seat reduced.

Are the bullets are truly seated out too far for your rifle? Take one of the Geco rounds, chamber it and inspect the bullet. Has it been engraved by the rifling? If yes, your diagnosis is correct. If the bulet is not engraved, then the probelm lies elsewhere, probably the cartridge's headspace exceed that of your chamber. I encountered this with PPU .308 Win ammunition in one P-H 1200TX (but not in the other PH 1200TX) and also with PPU .243 Win in a Sako 75.

-JMS
 
Since the S&B 140 grain ammunition fits fine and shoots fine, try to get a Hornady OAL comparator and measure those loads to the ogive. Then seat your hand loads to the same ogive, and see how they chamber and shoot. If all is well, record the OAL and there you have it for the next loads, even if you tweak the powder charge a bit.
 
I found 7x57 factory ammo to be very variable for some reason. Even had cases that wouldn't fit in one shell holder but would in another (can't remember which). I loved the calibre especially in a classic rifle but found the availability of factory ammo and components plus the reloading niggles to be a pain.
 
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