First things first DON'T SHOOT THAT AMMO ANYMORE. Contact Remington's ammo tech line. Tell them what happend maybe look on their site to see if they have a recall out. Sounds to my like they overloaded it. If there is a 800 number on the box then call it.
You mention a double explosion, I don't think that could happen. From what you say it sounds like a double charge of powder was put in the case. I find that hard also seeing as most loads fill the case up to the bottom of the neck or a little more. They might have gotten the wrong powder in the case. I would hedge my bets on wrong powder. Some pistol powders will allow a double charge but no rifle I have ever loaded would allow enough room left in the case even on a min load. Make sure to Set that ammo aside and mark on it so you don't accidently grab it on the way to the range again. Did the gunsmith completely check both rifles after this happend? If not take them to another gunsmith to have them checked out. If something came out of the rifle it was more likely a piece of the case or primer the came out. Did he give you the cases back after he extracted them? If not I would see if he still has them. If he still has them get them and send them in to Remington along with the unused ammo. Please keep us updated on your progress. Glad to hear you or your brother was not injured too bad.
Here is what i pulled from Remingtons web site.
What should I do with misfired ammunition?
Question
What should I do with misfired ammunition?
Answer
When there is a concern regarding our ammunition, we request that the ammunition be sent to our ammunition facility for evaluation and testing. To ensure proper shipping, we suggest the following:
Please package the ammunition in a secure carton or box. The package should be stuffed to prevent movement. Include your name, full address, phone number, and a description of the problem.
Shipment must be via U.P.S. only. For UPS, please mark the package "ORM-D" for Other Restricted Materials-D. Draw a box around the “ORM-D” letters and write “Cartridges, Small Arms” above the box.
Mail to:
Product Services
Remington Arms Company, Inc.
2592 AR - Highway 15N
P. O. Box 400
Lonoke, AR 72086-0400
We will contact you once our evaluation and testing have been completed.
