Help! I think my 700 chamber just let go!

I have been reloading for this particular 700 SPS chambered in 7 mag for about 4 yrs, bought it new. It has had some where around 1500 of my reloads through it, all using RL22 and never any sign of excessive pressures. Anyway, my brass has recently been showing what appears to be a radial fracture transfer from the chamber. Since I inspect my brass after each round fired, I saw the extrusion transfer on the brass from the initial point of origin as it quickly grew in radial size. I have not had a case head separation, ever, and can't imagine how, or why this could have happened. During the last 20 rounds the radial extrusion on the brass has increased in length from one round to the next. If I had been having head separations I could see how I would have damaged the chamber with gas cutting, but this is not the case at all. All my brass has always been clean and in good condition following each firing.

I'm bummed.

The common load I run, and the one's that I was running when this occured was 64.5 grains of RL22 and a 139 gr Hornady with necked Win brass, OAL at .010" off the lands, same load I have been shooting for ever in all my 7 mags. without incident. My brass has always looked 100% normal without any incipient head separations or gas leaks any where. I'm extremely anal about my brass inspection process and never use brass that is in question of being worthy to reload.
Anyone else ever seen something like this happen without any probable cause on the 700 SPS 7 mag.?

 

Just to verify are you actually seeing headspace increase over the course of 20 rds?

Have you checked headspace with a set of gauges?



Either way I'm more inclined to believe in a brass or resizing related issue before the gun till actual headspace is checked.




posted via that mobile app with the sig lines everyone complaints about

 

No, I have not checked head space, this is just the first and initial point of inspection. All I have right now is a radial separation inside the chamber, and brass that matches such.
GS

 

try just neck sizing so you are headspacing on the shoulder and not the belt.

 

Is this the same gun? April 2012 Post

http://www.thehighroad.org/showthread.php?t=655313&highlight=700+Chamber

 

The only reason it's going to do that is from a manufacturing defect. Call them and send it back.

 

I would be surprised if a "radial separation" found in the chamber after one shot did not lead to a kaBoom on the next. Or soon thereafter.

I would not shoot the gun any more subject to examination by a real riflesmith or the makers.

 

+1 on what Jim Watson posted. Have the gun thoroughly inspected by a qualified gunsmith before firing any more rounds through it. Since you are neck sizing the fired brass, it is most likely head spacing off the shoulder and not the belt which is a common cause of failure with belted cases that are FL sized.

 

Kind of confused here, in April, 2012, you said you had 5K - 6K through it, now its only 1500 through it.......... quite a few less rounds mentioned today, lose count?

 

I know Jim Watson. When he talks, you'd best listen.

 

No, it's not the same 700 as my April problem. That one was a very old ADL that had had who knows how many thousands of rounds through it, this one is a rather new stainless SPS.
And I will have it properly inspected when I get back from my hunting / fishing trip next month.
GS

 

Contact the Remington Repair center for AZ:
J&G Gunsmithing
7680 Barton Rd.
Granite Bay, CA 95746
(916) 786-9200
You may be out-of-warranty but they can still repair it at a reasonable fee.

 

Otto, do you think they would be willing to take care of my other older 700 one as well, the ADL.
I'll be honest here, if I thought for one moment if it was something I was, or have been doing wrong for the last 30+ years of reloading I wouldn't be advertising these catrostrophic failures knowing it was my stupidity that caused it. Additionally, I have never had a single problem with any of my reloads since I started doing this hobby. But I do load them full tilt most of the time, but only in a proper work up process, watching for any sign suggesting I'm breaching safe operating pressures. I don't encounter case separations, blown or leaking primers, or any case issues that indicate I'm beyond the limits. Do I use slow burning powders and push the envelope, yes, but again not to the extent that I ever, ever, separate or other wise breach the brass or primers. And the 7 mag is the only cartridge I've ever had a problem with at all, and the problem has been limited to these two awful incidents.

The only thing that comes to mind is that my Son bought several boxes of factory ammo when the rifle was brand new, and all but a few rounds of it would not chamber, and those that did would not eject without excessive force after being fired. Those were mixed brands, Remington and Winchester, so that leads me to believe that something was out of spec with the chamber from the get go?
GS

 

Just a "troubleshooting question". Please don't take is as questioning your skills or experience, I'm just asking what should be obvious questions.

Did you by chance load these rounds with a different batch of powder within the past calendar year? Could it be that these loaded cartridges are from the same lot that caused the problems in your other gun. Not catastrophic, but just enough over the limit to gradually wear out a gun at an accelerated pace. I assume you are weighing out the charges quite often since you are loading at the max.

Just asking questions that might help you get to the bottom of this.

 

“Anyway, my brass has recently been showing what appears to be a radial fracture transfer from the chamber”

I would suggest you learn to measure the length of the chamber from the bolt face to the shoulder of the chamber , I would suggest you learn to measure the length of the case from the head of the case to the shoulder of the case.

With all this memory work regarding head space I feel we are no closer coming to an understanding today than we were when it was introduced. As you can see the number of suggestions, “Check your head space” , then what? Go back to shooting the same old stuff.

Clean the chamber, purchase new ammo, purchase new cases, a fracture transfer from the chamber would mean the barrel is separating. I have claimed I have never seen skid marks on a case that has been fired in a chamber because I claim the case locks on to the chamber, benchresters are exempt. If what I believe is true and the case does lock onto the chamber when fired a case stretches between the case body and case head, and that is the reason I am the fan of cutting down on all that case travel. To cut down on case travel I must know the length of the chamber, or mindlessly pull the handle and get the head space checked as though sizing a case was not relative to head space (length of the chamber).

Firing a case in one chamber and firing it in another chamber with a different design can cause problems with the “we are no closer today....etc.”, back to eliminating case travel when fired, it is the best fix for both chambers. After all, It was Hatcher that moved the shoulder forward .080” with out case head separation, and we all know a case will not stretch .080” with out separating.

F. Guffey

 

Perhaps the case and the primer are not the limiting factor. IOW, perhaps the chamber/rifle can handle SAAMI max loads, but your cases and primers can handle considerably higher than SAAMI. If your rifle is cut to minimum headspace and/or you only neck size, you might never get a case head separation. Depending on the firing pin and breech design, the rifle could also be providing more support to the primer cup and case head than average; this could mask primer signs and reduce the propensity for enlarged pockets. So when you're pushing the envelope, you're not getting pressure signs, yet the loads are stressing the rifle. Seems like a plausible explanation, especially considering 7mm mag is one of the more powerful loadings for a 700.

Also, perhaps loading 0.01" from the lands is ok for accuracy loads. But maybe it's cutting it too close when you "do load them full tilt." Is it possible that a slightly malformed bullet could end up getting jammed in the lands, and your normally safe full tilt load is now an unsafe load? BTW, can you really load them that long with common bullet shapes and still fit the cartridges in the magazine?

 

Just out of curiosity, what does radial fracture refer to?

 

Find a smith with a borescope and take a good look inside the chamber. If you have a crack propagating with each shot, quit shooting it till you know what the inside of the chamber looks like. Magnaflux Spot Check would show an external crack but would be tough to use inside the chamber. An x-ray of the chamber would cost about what a re-barrel down payment would be.

 

It is odd that the same person has the same "issue" with two guns???? Something is not right with this equasion.

 

Same problem with two rifles in 30+ years of reloading but only months apart. I'm as baffled by this as most here in this regard. I had a friend come by earlier today and checked head space using a go-no go, all was fine.

As to brass and loads per action, I only use the brass that has been fired from the specific action that it originated from, and necked brass at that. The brass that I was using were well formed to each of those chambers, I know the brass was on at least it's 4th necking and had not yet been through the FL die. Either way, this is odd and does present a number of questions to address, especially for a long time reloader who has had nothing but uneventful years of reloading, that is until now. But I have not changed anything in the process in all those years.

Primers were normal appearing, CCI-250's, primer pockets were still in good condition, no leaks or loose ones.

Powder was from the same lot thoughout that load work up, up to that day. And I weigh each and every charge on my RCBS beam scale. And also, one of the first things I did was I checked the the scale using check weights.

And 64.5 grs. is not full tilt, although RL22 is a slow burning powder that produces upper to full tilt loads.

Seating off the lands .010" in that action is no problem at all and allowed for more than .284" of neck to bullet shank contact with those 139 gr. Hornady's, and yes, they fit the magazine with no problems. All my brass is maintained to within trim too lengths, I'm very particular about my brass in every aspect.

I've decided that when I return from my vaction I'm sending both of those rifles to Remington for inspection and proper diagnosis, even though the other one (ADL) is rather old and has had quite a few rounds put through it, RL22 loads at that. Nothing else looks out of the norm, the lugs are completely normal in appearance, and the bolt face isn't unusual looking. I'm no confirmed expert here, but I am very anal about my reloadong process and have never stepped outside the proper procedures since I began reloading in the late 1970's. I always use a scale for each and every cartridge and for every weapon I load for, except shot shells on my 600 Jr's. as they utilize powder bushings of course. But I use the scale to determine which bushing is throwing the desired charge.

I load for other older 7 mags, one is a custom M98 action / Douglas barrel, and load for family members 7 mags and a host of other high powered cartridges / rifles and all have been uneventful, other than the usual reasons for work ups and tweaking load specks to obtain improved accuracy.

GLOOB, I find your plausable cause to be a very possible explanation. This chamber is tighter than most 7 mags I load for. It is easy to get up to the lands without having to sacrfice any neck to bearing contact. I've had difficulty when I first bought the rifle getting factory ammo to chamber and or extract. Indeed I may have not been seeing signs of over stress, and especially loading full tilt as I do?

Thanks to all for your input, and I'll let ya all know what Remington has to say when I get their response.

GS

 

Thanks. It will be interesting to hear what Remington has to say. The dilemma would be whether to tell them that you are shooting handloads or not.

Borescope pix would be great.

Do you have any pix of the brass so others can see what to look out for? With those relatively normal loads, it could be an issue that others are having. They might not be paying close enough attention to catch it.

 

Kelbro, I'm going to see if one of my son's can assist me in gtting some picks posted. And no worries as to offending me, I'm just as capable of making a mistake as anyone.

As to what Remington has to say, I'm going to be 100% honest with them in that, both actions have had reloads almost exclusively put through them. And also that of the several boxes of factory that have been put through the SPS wouldn't extract, and most wouldn't even chamber. That right there indicates to me that something wasn't right with the chamber dimensions, and could be a major contributing factor.

As I had mentioned already, it has been no problem getting the bullets seated up to the lands while still providing plenty of neck to bullet contact and fiiting the magazine. Even 100 gr and 110 gr. bullets could be seated up to the lands and still maintain the recomended .284" of shank to neck contact.

Also unusual, when it became necessary to bump shoulders back, I had to adjust the FL die down as far as it could possibly go in order to bump the shoulders back at all.
GS

 

Remington's warranty doesn't cover the use of reloaded ammo (see link). But that's of little consequence if it's out of warranty anyway.
Rather than rely on internet-arm-chair gunsmithing advice, call J&G on Monday and tell them your problem. The last thing you want is a KB from a 7mm Mag.
Unless I'm wrong, you can ship the rifle using US Post mail.

http://www.remington.com/pages/support/firearm-warranty-information/2-year-warranty.aspx

 

Why if you was having problems loading factory rounds into the rifle from the get go didn't you have it checked out at that time?