Model 70 Problem

[Val]

Need some help. I've been developing a non lead load using the 150 grain Nosler E-tips in my Model 70 30-06. The max load of IMR 4350 for a 150 grain bullet in the Nosler manual is 59 grains. I did start lower and worked up to 59 grains which gave me three shot ,groups just under 1" which is what I normally get with this rifle. My last trip to the range I shot about 25 rounds and proved out the load. I always take care not to overheat the barrel and only shoot three or four rounds and let the barrel cool. I went to the range yesterday to chrongraph the load. The rounds which have an AOL of 3.355" didn't seem to fit all the way into the chamber and I couldn't close the bolt. It seems that some is keeping the rounds from going all the way into the chamber. I look down the chamber and can't see anything. What can I do to clear this? Any ideas on what may have caused the problem? I looked at the fired casings while developing the load and didn't see any signs of over pressure. Your suggestions and insughts will be appreciated. Thanks

[Val]

By the way, I been shooting 165 grain Partitions and Accubonds with this rifle and the same OAL for years. With 165 grain pellets I use 57 grains of IMR 4350.

[LONGTOM]

If you have rechecked the cases for size and all seems to be in order then my first thought would be powder build up in the chamber throat area.
Was the rifle cleaned between the last two range sessions?
Check the end of the bolt to make sure in is clear and clean.
Try a couple of other rounds of factory ammo that you have used before to see if they will chamber.
If they do then there is a problem with your reloads.
If they do not then there is a problem with the rifle.
Give the chamber a good cleaning if you haven't already and try them again.
If they still won't fit and the factory ones do then it is time to break out the calipers and start measuring your reloads.
These are just suggestions of things to look for.
I hope this helps and that it is just a minor problem.
Good luck and let us know what you find out.


LONGTOM

[Keith L]

And let us know what you find.  Thanks

[AtlLaw]

Just the first thought that struck me after reading your post a couple of times.  Bullet creep.  Reasoning follows:

developing a non lead load

I've never used one, but aren't "non lead" bullets longer then the same weight lead core ones?

max load of IMR 4350 <snip> worked up to 59 grains

IMR 4350 is my favorite 30/06 powder.  However, I seem to remember that I was compressing the charge with 150 gr. lead core bullets at less then 59 gr.  Now, I found that 4350 likes a little compression, but...  If you're using a longer bullet loaded to the same OAL it seems to me you would be compressing the charge even more then usual.

My last trip to the range ... I went to the range yesterday

Were all the rounds, the ones used during both trips, loaded at the same time?  How much time between trips?  In other words, did the second group of rounds fired have time to sit between shooting sessions giving the compressed powder a chance to sneak the bullets a little further out of the case.

an AOL of 3.355"

Did you measure the second batch prior to shooting them on the second outing, or was the measurement taken when all rounds were initially loaded?

Additionally, if the rounds were crimped they would be less likely to creep, but I think most of us don't crimp our rifle rounds.  Lastly, how far off your rifles lands are you?  Naturally, if you're close, as people are want to get, it doesn't take much forward movement of the projectile to hit the lands and make chambering the round more difficult.

Just a thought.

[Val]

I drove over and visited my gunsmith today. I took a powderless dummy bullet with me loaded to the same AOL i've used on this Model 70 for several years. Mike has been a gunsmith for over 50 years. He immediately knew what my problem was. He said that Model 70s should be loaded from the magazine and not directly into the chamber. He said that when loaded directly into the chamber that sometimes the extractor does not properly interface to the end of the casing like mine. He loaded my dummy round inmto the magazine and it loaded just fine. He said it could be to variations in the casings or from parts wear over the years. I've been loading my Model 70 directly into the chamber at the range for years and suddenly this issue came up. I'll just have to stick the round into the magazine for futire trips to the range. Anyone ever hear about this problem? The Nosler E-tips are 70 thousands longer than the Accubonds. They use some kind of copper alloy and their E-tips are not excessively long. I think it's a tungsten copper alloy. Thanks for the inputs guys. I think if I load from the magazine I won't have another problem.

[LONGTOM]

I guess it is possible, although I have owned and shot over a dozen model 70s both new and old in many calibers and have never ran into that problem, or ever heard of anyone else ever having that problem. Yours must just happen to be that elusive exception to the rule!
I hope he is right and all works fine from here on out for you.
Thanks for posting your findings for the rest of us who one day may run into a similar problem.


LONGTOM

[Mikey]

Val - Mauser bolts will not close on a round unless it is fed from a magazine.  I have two M70s, one a 1970 vintage and the other a pre-war (WWII) vintage.  The newer rifle will close its bolt on a round dropped into the chamber but I haven't yet tried that with the older one. 

Winchester changed the feed style, from controlled to push (I think) in 1964 but I don't know if that is an issue with your rifle. 

However, you stated that you were using a specific type of bullet and although your oal may be the same, the ogive on the bullet may be such as to prevent a proper chambering and bolt closure.  I encountered that once with a 308.  You may have to seat the non-lead bullet a tad deeper if this is the problem.  JMTCW but HTH.  Mikey. 

[Val]

Mikey,
You are correct. The Nosler E-tip turns out to be about 70 thousands longer than an Accubond in 150 grains. I reduced the OAL by 10 thousands and the rounds feed well out of the magazine. Even the older loads that I'v shot in this rifle for years are having some problems when fed into the chamber. Maybe it's wear on the mechanism that has caused this. I've fed directly into the chamber for many years and all of a sudden I came up with this feed problem. I'll just have to get used to feeding from the magazine. I'll be back to the range in a few days to chronograph my E-tip load.

[Cecil]

Val Is it a push or control round feed, The control round should not be loaded dropped in to the chamber as it forcing the ejector out pretty far to except the base and could cause it to break. If its a push feed I would check the extractor to See if something is blocking it from opening all the way. Hope this helps

[Val]

It's a control round feed I believe. It has a little claw like thingy that fits around the rim of the casing. By the way I chronographed my 150 grain E-tip load and its pushing them out at 2994 fps. The rifle shoots well so I'll just have to get use to magazine feeding at the range. While hunting I always magazine feed.

[Rangr44]

You have developed an abnormal situation, and (since you've used the gun a long while w/o probs) it's most likely attributable to some change you've made recently - like to the ammo.

A 2nd possibility is "build-up", behind the extractor of a push-feed action, not allowing the extractor to snap over the chambered cartridge's rim - pushing it deeper.

BTW - It's not a controlled-round-feed (CRF) unless it has a full-length (claw) extractor running along the right side of the bolt.

If it's not there, it's a push-feed action, with the smaller extractor working in the boltface.

Commercial (not military) CRF bolts have a little angle stoned into the end of the claw, which allows the extractor to cam itself over the rim of a cartridge dropped directly into the chamber, with the bolt then closed behind it.  Military action's extractors are easily so modified, for sporting use.