I am reloading a 22-250 IMR4895 with 34.3 grains of powder. 55 grain soft points. Full length resizing. Cases trimmed. About every 10th round the case blows in two right where the thick part and the thinner walls of the case join. About one half inch from the base of the case. The rifle is a Huskavarna that I have had about thirty years. I always thought that I may have loaded them to heavy, but I have been checking them twice with a powder scale and also with a Lee Dipper.
Can any of you help me with this problem? I would like your input as to what is going on. Thanks

After the case blows up, does the next round blow up also? Do you think the case is blowing up because the rifle's barrel has become dirty, and caused increased pressures? Is it hard to unchamber the rounds before the case blows up? How old are your cases? Are all your cases exactly the same? Have you checked them for case head separation? Good luck.

The cases are trimmed all to the same length. Only about every 10 to 15 is blowing up. The barrel has been cleaned. Maybe I should clean it after every four or five rounds. The brass is twice fired...

Need to have your headspace on your rifle checked.

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I could have mixed some old brass with the new ones. I am going to neck size only the next batch. I shot about 8 times this morning with no signs of bulging, so the cases might have been old. I think that if the head space was to big that they all would at least bulge. I am also going to drop back to 33 grains of IMR4895. Thanks very much and I will let you all know how the next batch does...

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I concurr 100%.........

While neck sizing only will help the situation the correct solution is to reset your chamber back one full thread of the barrel tenon. This can cost about $100 and requires a small amout of rechambering.

What you have described is a classical headspace problem.