Home Forums Hunting & Shooting Hunter's Campfire model 70 explosion

Yes, we all know the case failed. The question being discussed is in what sequence the receiver failed.




You are right that the Mag boxes are the same length. The issue is how was the receiver modified. We know it had to be. I have hundreds of pre-64 model 70s in my shop every year. We build custom rifles on the the model 70 action. More importantly, people send us their jacked up rifles to have us fix what other “gunsmiths” have screwed up. When people can’t get the belted Mag cartridges to feed, they often grind the feed ramp. The reason they do this is because when you try to feed a belted Mag in a standard action the belt causes the action to hold the base of the case too low in the box while the bolt is coming forward. The crf bolt face doesn’t grab the back of the case so the bullet tip ends up angled too high and jammed into the top of the cone breech. If a smith does not realize what needs to be changed, they are sometimes baited into thinking they can bring the feed angle down by lowering the ramp. I have a junk drawer of receivers which have received this exact treatment.

Look, I don’t have the time or interest in having a pissing match with you about the details of how these actions are designed, supposed to work, or how they are often modified, so I’ll just bow out. But you really should check your ego at the door to help the OP get the most out of these conversations. Some people who come onto these sites bring very specific knowledge. If this was a Rem 700 thread, I wouldn’t pretend to know anything. But the reality is I see and work on hundreds of pre-64 Winchester rifles every year. It’s the only gun we work on. It’s just possible I know a thing or two about the way this action works.

You don't know this. Nor do I. If the case failed, we are dealing with a severe overload or wrong cartridge scenario. I am taking the shooter's (via the OP) word that this is not the case and the round was a factory load. Keep in mind, when it comes down to what came first, it is a matter of microseconds in the chain of events. I have seen cases where an action was shown, upon examination, to have had an incipient failure. A weakening of the receiver, along the corner of the right hand raceway, was unnoticed but failed after several shots. The result didn't look much different than what is shown here. I have also seen some which came apart due to severe over pressure (wrong powder or wrong ammunition) and they didn't look a lot different. Right now, this effing site is making it almost impossible for me to type without cutting me off while it displays soft core porn so I'll have to give up on it.
I would like for someone to describe to me the classic signs of excessive headspace, shown by the case which was fired BEFORE the action came apart.
Am I the only one who has problems with this site? GD

Excess headspace creates a hammer effect with the bolt. Essentially giving it enough of a run at the receiver lugs to slam the bolt backward into them. This has the effect on the shooter of feeling like a massive recoil (if the action holds together). Often excess headspace breaks the stock because of the energy the stock sees when the bolt impacts the receiver lugs. If you look at the photos, the entire recoil lug portion of the stock inletting is sheared out of the rest of the stock. To me, this is a good indication of a massive recoil. Many times more energy than a hot load with a heavy bullet could cause. Also, excessive headspace will rupture the cartridge at the base, where it is not supported by the chamber. If you look at the photos, you can clearly see a rupture on the left side of the case. To me, these both indicate a headspace issue. Not conclusive, but a really good indicator.





GrayDog, I have not been here in over a year, but I am with you 100% What is the deal with the garbage ads? It used to be gun companies advertising on this site. Honestly, it's a good enough reason to stick to some of the other discussion sites that seem to have better control of their sponsors.

If it was excess headspace, why would it fire one round without issue, then let go catastrophically with the second round? It appears the gun had been functioning without issue well before this young man's range session.

If you look at the first case which was fired, the primer is not unduly flat (this can be a sign of excessive headspace), there is no sign of an incipient head separation (another classic sign of excessive headspace), and there is no ejector slot mark which, again, can be a sign of excessive headspace. This leads me to believe head clearance was not an issue until the receiver failed!
By the way, I have a pre-war Model 70 which was re-chambered to 308 Norma in 1962. I have re-barreled it three times since then. The rails are untouched and it feeds and functions perfectly. GD

Do you guys have a good ad blocker on your computer? It will do wonders to get rid of the incipient ads and they are free to download. Also, delete your cookies once in a while and you will get away from a lot of the tracking ads and BS that comes along with them....

Its not about my ego, it's about your blatant
basic ignorance concerning 7 mag OAL,
then based on that ignorance you allege
the feed ramp was modified to accommodate.

But alas two long paragraphs of sidetrack
waffle to tell everyone what an expert you are. .



Ive never dealt with a custom shop that works
on hundreds of bolt rifles every year even with
a small skilled crew.

but you alone personally work on hundreds annually.

Its comes down to quantity vs quality.

Keep in mind that IF it's operator error it would be stupid to post it publicly.

Not that it would matter to you Starman, but do you have any idea who you are arguing with. He has forgotten more about the pre-64 action than you will ever be able to copy and paste. Do yourself a favor and just read and learn.

IF you want to 'learn' from someone who
doesn't even know the OAL of 7 mag
go right ahead.. 😂.. Coz you know he
works on hundreds of pre64 every year...
I don't know of any top level pre64 smiths
(with any repute) that do anywhere near
that crazy number.

Go talk to Echols, Penrod, Jerry Fisher,
Ralf Martini, etc.. or any ACGG member
and ask how many rifles they have turned
out a year.

If I misstated the OAL of the 7mm RM, please point it out. I will save you the effort - I didn't. What I did do was explain why the feed of any of the longer belted magnum rounds from a standard action can bait a gunmaker into thinking they need to modify the feed ramp. Shorter belted magnums won't face this same issue because the belt will center and rise into the CRF bolt face as soon as the standard receiver feed rails push the cartridge to the center.



At least you can admit you don't know some things. And it's clear you don't know us. Our shop is 100% dedicated to the pre-64 model 70. It is all we work on.

You stated 7 mag is 'pretty long' yet fact is
its no longer than the regular vanilla 270win
and Winchester belted magnums.

I'd say that Federal ammo is made to length
to fit into many ordinary production rifles.

Well perhaps you would fill us in on who he is?

Don't know the gentleman's name, but have bought pre-64 parts from his company and talked to someone there a few times about a model 70 I was working. Genially good people to deal with and very helpful over the phone. Not saying he is in the same category as Starman about all things internet searchable, but I'd buy parts from him again and ask for his opinion if I needed to know something about a pre-64 Winchester.

Hey Chucktool if you go to SCI and ACGG
you get to meet and talk to those smiths
I mentioned, even get invited to their homes.

They also dont go on Forums trying to convince
everyone what experts they are, coz they don't
need to.

Be alright if I mention that an idiot named Starman send me? I would like to know what I'm walking into if you know what I mean.

A reminder of the original post.

Chucktool,
So you've bought factory pre64 parts
but never had a quality custom done,
well if you do go, best you don't waste too
much of those smiths time... you can still
touch the display rifles if you ask and get
your rocks off... the guys you will find are
quite understanding.

Foolman, I spent the morning doing barrel break-in on a new Christensen Arms Mesa and sighting in a new VX-3i CDS-ZL scope I bought myself for Christmas. Other than arguing with an actual Gunsmith about something you have no clue about, what did you do?

Lol. A good reminder from the guy with 7,700 posts to the guy with 170 posts why I stopped coming to this place. I will leave you to fill in everyone on everything. They clearly don't need any other perspectives.



Amen.