22/6mm bullets blowing up

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by bearmn56, Feb 5, 2012.

  1. bearmn56

    bearmn56 Member

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    Feb 5, 2012
    New to this site....but not new to shooting. I started working with the .22/6mm several years ago. First barrel was a Montana Rifleman...gain twist to 1 in 8". Did not work out...bullets blowing up...even the heavies...69,75,77,80s. Went to a 1 in 8" Hart barrel. Shot fairly well...Sierra 80gr MKs the only thing that would stay together....most of the time. Throat gone after working up loads and one prairie dog hunt.....bullets would explode or fly erratically. Two years ago had a 30" Lilja very heavy barrel installed...3 groove, 1 in 8" twist. Everything blows up except solid copper 70gr Barnes and 75gr Swift Scirroco IIs. Bullets that blow up leave their jackets about 25 yds in front of shooting position....they look like little copper dimes. The ones that don't blow up quickly show grey lead halos around the bullet holes at 25yds and often don't make it to 100yds. Examination reveals that they have split along one of the grooves created by the lands. Dan Lilja says that his 3 groove barrels are the best.....Doesn't understand why everything is not working out. Have done nothing with the rifle for two years...in the gun safe. Want to get it going...Have heard of the "new"??Berger "Thick Jackets" and wonder if they will work without blowing up. So, two questions.....Is anyone else having the blowup problem with the ultra high velocity .22s? Does anyone have any solutions?
    Have spent a zillion dollars on this project and would be open to ANY suggestions.
    Respectfully,
    Bearmn56
    Montana Territory
     
  2. davewilson

    davewilson Well-Known Member

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    Dan says his 3 grooves are the best...for what? i think the 3 groove thing came and went, they are just harder on bullets. to be honest, i doubt you have a twist problem, but being you're probably close, anything else will "put it over the top" so to speak. if you want to scream them out of there, get some GS customs. you won't blow them up. my guess is you have a crackling problem that's very prevalent with the fire breathing dragons. a new barrel is very smooth, and doesn't tear at the bullets. but as you shoot, the surface of the grooves gets cracks in it, as the number of rounds increases, the farther the cracks go down the barrel. these cracks have more to do with dusting than the rifling. also remember the faster you push bullets, the higher the rpm's are and the greater the centrifugal force which is another reason to come apart. if you want to shoot a long ways, you have to use the longer bulets which take a faster twist. if you're concerned with speed, put a 14 -15 twist on it and shoot the lighter bullets. i doubt the bergers will work better, i would assume quite the opposite. the reason the scirrocos stayed together is because they are the thickest jacket of the bullets you mentioned. and 5 or 6 lands is just better.
     

  3. bearmn56

    bearmn56 Member

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    Feb 5, 2012
    Dave,
    Thanks for the reply. I kind of suspected that the three groove barrel might be a problem (when I ordered the barrel from Lilja, I told him that it would be used for a 22/6mm with heavy bullets...the 3 groove is what he sent)... I can see that the forces of accelerating and spinning the bullet...as imparted through the jacket..were only divided between the three lands probably weakening the jacket at the junction of the lands/grooves. (My gunsmith recently showed me a new Broughton barrel...5 radiused lands and grooves...no sharp edges to create problems... a truly gorgeous barrel.)...By the way, in a phone conversation with Dan Lilja, he insisted that sharp edges of lands were best for accuracy...just saying what he is saying...
    One other option that I have considered is to have the 22/6mm chamber cut off and have the barrel set back and rechambered to 22-250. Have a friend who has a 1-8" twist 22-250 (six lands and grooves). Claims to be getting around 3100-3200 fps with 80gr SMKs and no blowups. He also claims a rather high shot count with minimal throat erosion (this guy has everything including a bore scope!!).
    The Lilja barrel was over $500.00 installed (using my JGS custom reamer with no throat...just a short leade allowing the Sierra MKs and Berger VLDs to be seated with the base of the bullet at the base of the neck). Kind of hate to change barrels again until I find a proven combination.
    Thanks again,
    Bearmn56 (Bill)
    Montana Territory
     
  4. Varminator 911

    Varminator 911 Well-Known Member

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    Dec 7, 2007
    22-250AI has a lot going for it. Enough velocity for the heavy pills, good barrel life, and easier on the cases than standard version.
     
  5. MachV

    MachV Well-Known Member

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    May 31, 2001
    Too much of a good thing.
    Was advised years ago to use a nine twist but already had the 8 so instead of going 22-243 or 22-6mm I just stayed with the standard 22-250. So far its worked out good as the 75 A max @3350fps turns the 22-250 into a whole different animal than the 40/55 grain 12/14 twist version
    Three grove barrels tend to last a bit longer but are hard on jackets.
    for what its worth the GS bullets dont shoot worth a tinkers damn in the 8 twist 22-250 but do alright in the 223ai 9 twist?? niether of wich I can hunt big game with in WY and too spendy to use for dogs.
     
  6. Loner

    Loner Well-Known Member

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    Apr 14, 2010
    You would need some shallow button rifling in a 6 or 7 land barrel. Deforming the
    jackets less but still enough to spin them up. Or shoot solids.
     
  7. bearmn56

    bearmn56 Member

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    Feb 5, 2012
    Thanks for your ideas, guys. I will have to weigh my options and decide what to do. I like the 22-250 idea. The action that I am using is a new M70 Winchester stainless short action CRF in a coyote stock. The tightwad part of me just wants to make the 3 groove Lilja work.:rolleyes:
    Bearmn56
    Montana Territory
     
  8. Gary2881

    Gary2881 New Member

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    Mar 17, 2012
    I have two rifles in this cal. My first is a Mauser action with an 8 twist Kreiger 30" heavy stainless barrel with a muzzel break. The Sierra 80 gr. shoot the best. This rifle is so heavy that it is pretty much a bench only gun, but still much fun.

    Since I liked the 22/6mm, I built a more portable model. I rechambered a stainless, 22-250 Savage varmint barrel and mounted it to a long Savage action. I use this rifle with 55gr bullets to shoot Nutria across grass seed fields. Usual shots 400 yds. It seems to hit them harder than my 22-250AI.

    I wish I could help with this problem, the 8 twist barrel only likes the 80gr. Sierra's, but otherwise is very easy to load. As far as I can tell, I have not had any of these blow up. When I bought this barrel, I got several thousand bullets from the same batch, and that is the only ones that I've used. Maybe you need to try a different batch of bullets? Also, is it possible that your load is too hot and you are driving them too fast ? Don't know if that is posible.

    Any way I hope you get this sorted out. Both of my rifles are about as trouble free as any of my others.

    Gary
     
  9. Varmint Hunter

    Varmint Hunter Well-Known Member

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    Dec 26, 2001
    For several years I shot a 22-243AI with an 8" twist. I always moly coated my bullets and loaded the bullets into the lands. I never had any bullet blow up. I believe that the moly relieves a lot of jacket stress as it is engraved by the rifling. Loading bullets into the rifling avoids the impact of bullets slamming into the rifling. These two things combined may have gone a long way into preserving the structural integrity of the jackets

    The rifle shot best with the 75gr A-Max (moly) even though I intended to shoot the 80gr SMK.

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