Home Forums Hunting & Shooting Gunsmithing Fireforming question

Glad there's lots of smart fellers here. I have a XP100 I can't identify the chambering. It started out as a 7BR and has obviously been rechambered. Grasshopper was nice enough to send me a dummy 7IMSHA, when chambered it won't extract and a 7/08 is too long. I suspected extractor issues, so I tried the suspect bolt in my other XP and it does extract.

I'm wondering if it would work if I use the cream of wheat fireforming on a 7IMSHA case then measure the case?

Thanks, Jim

Take it to a gunsmith and have him make a chamber cast.

I'd like to, but the nearest 'smith is 110 miles. Karl Kenyon does live here, but he's in tough shape.

I've used the cream of wheat method for fire forming 30-06 to 35 Whelen. It works great. a light charge of pistol powder, then fill to the top of the neck with cream of wheat. Got to hold it straight up to load and fire.
Virgil B.

you can drip candle wax over the top of the cream of wheat, or press in some play dough, or slice of Potato.

You can order Cerrosafe from www.midwayusa.com and chamber cast it yourself. I would prefer that to anything else. 7mm chambers are so diverse there is no telling what it may be.

+1

Do you mean the 7IMSHA is driven into the chamber so the extractor won't grab it? Or do you mean it sticks in the chamber? Be careful here.

I've fire formed with corn meal blanks using cast bullet lube to plug the neck. The thing is if it goes in to far to let the extractor grab it and still managed to get hit hard enough by that rebounding firing pin to set it off I'd worry about a head separation. I'd order the cerrosafe and do a chamber cast. It melts at very low temps. Just read up on it first.

Just tried it again, and it is driven into the chamber, but after opening the bolt it won't eject but will slide out. Tried it with another bolt with the same results. It acts like the extractor isn't climbing over the case head. A 7/08 lacks about 3/8" (I'm a carpenter, not a machinist) from chambering.

Leaning toward the Cerrosafe, thanks for the replies, guys!