I recently had my model 70 re barreled to 7mm rem mag using a factory barrel. The bolt face was opened up to mag spec and the barrel was set back one thread and reamed to head space. I just went out shooting and noticed that four rounds out of a box of super x 150gr power points wouldn't allow the bolt to fully close and bring the rifle into battery. The chamber appears smooth as well as the throat and shoulder. It shoots fine but I'm concerned with future use. Anyone have a suggestions?
rebarreled my model 70
- Thread starter Visionz45
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MMCSRET
Member
If 16 rounds chambered and 4 rounds did not and it was a box of factory ammunition and not a mix of ammunition then I suspect you have 4 rounds that are out of spec for any number of reasons.
More information needed:
1. was all the ammunition from the same box and same brand
2. was any of the ammunition mix or match, odd lots
3. was any of the ammunition hand loads
All these questions have to be answered, if the ammo was new and all the same box, then a trip back to the gunsmith is called for or you got a box of ammo from a bad production run. Anything is possible and can not be identified from here, but eliminate the possibilities of problems one by one.
More information needed:
1. was all the ammunition from the same box and same brand
2. was any of the ammunition mix or match, odd lots
3. was any of the ammunition hand loads
All these questions have to be answered, if the ammo was new and all the same box, then a trip back to the gunsmith is called for or you got a box of ammo from a bad production run. Anything is possible and can not be identified from here, but eliminate the possibilities of problems one by one.
All of the rounds were of the same box, winchester super x 150gr pp's. There is some marring on the body of the case now that I went and re-inspected them. Secondly I can close the bolt on the round but it is really stiff. The lands don't appear to be engaging the bullet itself. Could head space be fine and the chamber just tight? I don't want to experience that unusual bang and have my floor plate blasted open and bolt froze shut.
BADUNAME27
Member
These are a few other possible reasons. It doesn't sound like some really apply to your particular case, but if nothing else it'll rule out a possibility or maybe help a guy out later in life.
Your rifle is a repeater. Are you loading your magazine and then punching holes?
It's a 7mm Remington Magnum, a high energy, high velocity cartridge. I would suggest you try a test. Single load two, three rounds. Don't fire. Just check to see if they chamber. Now load your magazine and shoot a couple. Save the last round and pull it out. Compare the COAL with the others in the box.
Has the seating depth of the bullet changed?
Recoil affects everything, to include the cartridges the magazine box. Not saying this IS the answer to your problem, but it is something that does happen more frequently than a guy realizes. It's precisely why a great deal of sporting type ammunition has a cannelure groove in the bullet, so the case neck can be crimped to mitigate the bullet being pushed around during recoil.
If you are concerned about ruptured cases and trips to the hospital, then I would strongly encourage you to stop what your doing, double check the chamber headspace (which requires completely stripping down the bolt of all it's peripherals), obtain a brand new box of quality factory loaded ammunition, and then carefully cycling a sample of rounds through the gun to ensure it's chambering properly. It would BE BEST to do this with the bolt completely stripped of its fire control so that there is NO CHANCE for it to fire accidentally. (this means the striker and striker spring are removed from the bolt)
If your rifle was chambered with a minimum SAAMI spec. reamer it may also be the problem. I have run into this before. Typically with cartridges that are more common in competitive/tactical shooting. A min spec chamber in 338 Lapua Magnum for instance will almost always work just fine with Norma brass. This same gun will quite likely be temperamental when attempting to use Lapua brass. Reason is Lapua tends to run towards the bigger side of the SAAMI tolerance. Not a thing wrong with that. In fact it can be beneficial if a guy's rifle is chambered in a standard size chamber. It's not until you start clamping down on the chamber dimensions with a min spec reamer that the "problem" presents itself. You may very well have a similar situation.
Hope this helped.
Chad
Your rifle is a repeater. Are you loading your magazine and then punching holes?
It's a 7mm Remington Magnum, a high energy, high velocity cartridge. I would suggest you try a test. Single load two, three rounds. Don't fire. Just check to see if they chamber. Now load your magazine and shoot a couple. Save the last round and pull it out. Compare the COAL with the others in the box.
Has the seating depth of the bullet changed?
Recoil affects everything, to include the cartridges the magazine box. Not saying this IS the answer to your problem, but it is something that does happen more frequently than a guy realizes. It's precisely why a great deal of sporting type ammunition has a cannelure groove in the bullet, so the case neck can be crimped to mitigate the bullet being pushed around during recoil.
If you are concerned about ruptured cases and trips to the hospital, then I would strongly encourage you to stop what your doing, double check the chamber headspace (which requires completely stripping down the bolt of all it's peripherals), obtain a brand new box of quality factory loaded ammunition, and then carefully cycling a sample of rounds through the gun to ensure it's chambering properly. It would BE BEST to do this with the bolt completely stripped of its fire control so that there is NO CHANCE for it to fire accidentally. (this means the striker and striker spring are removed from the bolt)
If your rifle was chambered with a minimum SAAMI spec. reamer it may also be the problem. I have run into this before. Typically with cartridges that are more common in competitive/tactical shooting. A min spec chamber in 338 Lapua Magnum for instance will almost always work just fine with Norma brass. This same gun will quite likely be temperamental when attempting to use Lapua brass. Reason is Lapua tends to run towards the bigger side of the SAAMI tolerance. Not a thing wrong with that. In fact it can be beneficial if a guy's rifle is chambered in a standard size chamber. It's not until you start clamping down on the chamber dimensions with a min spec reamer that the "problem" presents itself. You may very well have a similar situation.
Hope this helped.
Chad
Last edited:
MMCSRET
Member
The magnum is designed to head space on the belt, inspect and see if that is indeed what is happening. If your chamber is too short and the case shoulder is touching before the belt is seated, you are spacing on the shoulder then you need a trip back to the gun smith for a better finish ream. If you hand load you can tailor your case sizing to accomplish this with out more polishing or reaming.
Thanks for the input. Ive checked the belt area of the chamber and its all clear. I'm assuming that the headspace is fine if most of the rounds chambered fine and only a few chambered fairly hard. Ive poked around on the internet and seen people having the same problem with winchester super x ammo and atributed to "tight chambers". Its never been a problem for me and I'm going to try the doubletap 140gr accubonds my friend gifted me then hopefully use that brass to reload with. Ive done the steel wool on a cleaning rod/power drill trick before with good results. Lastly ive been told that asides from not having excessive headspace I should be fine, I just dont want anypiece of that rifle visiting my head at light speed.
moooose102
Member
it is possible that the majority of the ammo in the box has shorter than max. spec case lengths, and when you get a few that are very near (or at) max length, the case neck is hitting the end of the chamber. see if the case lengths are longer on the unfired rounds, than on the fired ones. i have noticed quite a bit of fluctuation in case lengths when i buy new winchester brass to load. i run all of them through the forster case trimmer, and set them all at the same length before i load them. if this is indeed the case, then it will be back to the smith to have the chamber cut a few thousandths deeper. a tight chamber, that is in spec, is a good thing. brass (for reloading) will last much longer than if you have a loose chamber. you will also get (slightly) more velocity from your factory shells, as less energy is spent expanding the case dimensions and more goes into pushing the bullet out of the barrel. whatever the case, it is important that all factory ammo will work in your gun. if you ever forget your precious handloads, and you are 15 states (or out of the country) away from home, you at least want to be able to go into a store and buy something off the shelf! i have had some of my hand loads be a little hard to close the bolt on, but every factory round, no matter if it is winchester, remington, federal, or even foreign stuff has dropped right in.
Funny thing I just called the smith at his house earlier and he swears that its a-ok in the headspace dept. and that the chamber might be a little tight. He says hes heard of this problem and actually mentioned winchester as a likely culprit. Ive toyed with it some and cleaned the chamber and it seems to have improved a little. Im still on the fence but it does shoot quite well and he say to have had no problems during his test fire. The doubletap feeds fine so now im leary of winchester ammo.
If I had cut the chamber I would be able to tell how much head space your rifle has in thousands, a chamber cut by someone else? No problem, purchase new cases or purchase a few once fired cases from the range, cut them off in front of the belt, because it does not matter make it one inch, if you reload size the cut-off cases then try to chamber, if the test cases chamber without resistance to bolt closing check the chamber length from the face of the bolt to the shoulder of the chamber, again new or once fired cases will work, I cut the belt off of the case, neck the case up to 338 or 308 (I use a 308 Norma Mag or 338 Winchester Mag sizer die) then start necking the cases down with the 7 Remington Mag die, BUT, with a feeler gage, adjust the die off of the shell holder with the ram up, I start with a gap of .012 thousands, after moving the shoulder back attempt to chamber, if the test cases will not chamber, decrease the gap to .008 and attempt to chambering the cases again, if you do not get consistant chambering before you get to .000 gap, the chamber is short, I will not say 'not a problem' I would adjust the die down to the shell holder with an additional 1/4 turn (what ever that is), secure the die and continue sizing but with a feeler gage between the deck of the shell holder and bottom of the case, this sizes the case for short chambers, I short chambers first, then road test, if after road testing I like the results, I finish the chamber.
In the perfect world the belted case can not be shimmed up more than .004 to .005 thousands, that is the reason I cut the belt off when checking for short chamber.
F. Guffey
In the perfect world the belted case can not be shimmed up more than .004 to .005 thousands, that is the reason I cut the belt off when checking for short chamber.
F. Guffey
I had another smith headspace check the rifle and he say its fine. The chamber was reamed using a minimum saami spec reamer. He say its fine and told me to polish the chamber and try another box of super x's. Even though I'm not going to shoot the winchester ammo I went and bought some more and tried feeding them after toying with the rifle some more. Two of them chambered "kinda" hard but nothing to bad and the doubletap ammo chambers pefectly. Its improved and it drives tack so maybe I lucked out. Thanks for the input, it alot of help.
"and he say its fine" That is the reason I do not have a lot if confidence in Sammy specifications, a go-gage should be a go-gage, that would be a chamber that is .005 longer from the bolt face to the shoulder when compared to the distance from the head of the case to it's shoulder, the case is .000, the chamber is .005, no go-gage is .009 and the field-gage is .014.
The only results that has a value is 'How does factory ammo fit the chamber'
Again, I purchased a mill from a collector and resource person of M1s and 03, while loading the mill and related parts a question came up about head space, he was building an 03 that was correct for 1911, there were no head space gages he did not have, because I do not shoot gages I ask him for the ammo he was going to use, he has no less than 50 03 bolts but only two were straight handled that would be correct for that rifle. No matter what when he checked the rifle with gages the go-gage chambered, the no go-gage wouldn't. I checked the effect his new Remington ammo had on head space, there was .0017 thousands difference between the 20 cases, when head space was checked using each case the rifle had from .0065 to .0082, I offered to check the effect each bolt had on head space with his new ammo, I also offered to form cases that would reduce head space by as much as .005. Anyhow, I was wanting to check his press, he adapted his press to operate with a hydraulic pump and cylinder(s).
F. Guffey
The only results that has a value is 'How does factory ammo fit the chamber'
Again, I purchased a mill from a collector and resource person of M1s and 03, while loading the mill and related parts a question came up about head space, he was building an 03 that was correct for 1911, there were no head space gages he did not have, because I do not shoot gages I ask him for the ammo he was going to use, he has no less than 50 03 bolts but only two were straight handled that would be correct for that rifle. No matter what when he checked the rifle with gages the go-gage chambered, the no go-gage wouldn't. I checked the effect his new Remington ammo had on head space, there was .0017 thousands difference between the 20 cases, when head space was checked using each case the rifle had from .0065 to .0082, I offered to check the effect each bolt had on head space with his new ammo, I also offered to form cases that would reduce head space by as much as .005. Anyhow, I was wanting to check his press, he adapted his press to operate with a hydraulic pump and cylinder(s).
F. Guffey
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