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Project Research for a nice 32Rem and a "B" 35Rem

Posted: Tue Feb 12, 2013 1:03 am
by Phyrbird
I'm thinking :idea: (Whoops) on a possible project. Got some fitting questions:
How much "fitting" is involved to mate a bolt to a barrel? Aside from the concept of headspace.
What are the case SAAMI dimensions for 32R, 30R, 25R? Source for gonogo headspace gages?
Doesn't the 35Rem and the 300 Savage have very similar rim dimensions. I've seen photos of a 300 Savage with a 35 on the Extractor.
Are there significant differences in magazines from caliber to caliber? I'm pretty sure there are from Model 8 to 81 with a few iterations in very early Model 8s.

These rifles were built in another era, how close are the tolerances from rifle to rifle?

I'd also be interested in tracking some of the alternative "Krieger conversion" removable magazine Smiths. Can you help?

Re: Project Research for a nice 32Rem and a "B" 35Rem

Posted: Tue Feb 12, 2013 9:44 am
by 81police
I believe the factory sorted the headspacing through adjusting the barrel extension (block the barrel screws into). If I'm wrong someone please correct me!!!!

35Rem and 300Sav used the same extractor, so finding a 300Sav with an extractor marked "35" is normal.

Considering the rifles were machined on equipment not controlled by computers and each rifle built by hand, surprisingly many parts are compatible from gun to gun.

Most non-Krieger magazine conversions were done by individuals in small shops whose names have been long lost. I think one member here was toying with making his own detachable magazine variant.

Re: Project Research for a nice 32Rem and a "B" 35Rem

Posted: Mon Feb 25, 2013 10:36 pm
by Phyrbird
OK, I've done some digging. The 35R bolt is about .005-.007 smaller than the 300Sav. Looking at the cases in the chambers with the rifle taken down they are very deep. That is the extractor is recessed in the "block". Yes, the extractor is very much the same. I'm amazed that the bolts close on all the barrels if they are the same rim family. It works!! :o The precision these rifles were built with is amazing considering the era of their manufacture. I'm not saying the headspace is correct just yet. I'm working on a method to check them. Anyone have sets of 25R, 30R, 32R, 35R, and 300Sav headspace gages I could borrow?

Goal: I'm also a TC Contender FreaK, the possibility of a swap barrel custom gun seems like a cool idea. :idea: Mr Browning just didn't think of it. (Maybe ;) )

Warning: I am NOT advocating swapping barrels and bolts around without a thorough check of fitting & headspace. This is not for amateurs.
SAAMI data:

I acquired a 32R rifle recently with a Non-Kreiger removable magazine. It's a very simple mechanism; the latch is on the trigger guard bottom, same as the Kreiger, it operates in the opposite direction. There's a spring that holds a catch against the shoulder on the back of the factory mag. The only mag mods required are fixing the springs to the sides of the magazine and filing a curve on the back of the magazine to allow it to catch in front then rotate up till it latches. It also requires the screws on the left side & a small slot in the front of the trigger guard for the latch. Oh, a pin to hinge the latch. While I've never had a Kreiger in hand, from looking I think this one is very KISS principal.
I'm planning to post photos on the Pics folder soon as I figure it out.

Note: I've not done any firing just yet, but my 35R and 300Sav barrel assemblies fit and the actions close. My 32R, 30R, & 25R all mount and close on a 32R receiver and a 30R receiver.(luck perhaps) I do have some concerns of the extractor fit in the barrel block. Working....

Re: Project Research for a nice 32Rem and a "B" 35Rem

Posted: Tue Feb 26, 2013 4:44 pm
by DWalt
Headspace is not likely to be a problem for you. Having headspace gauges won't help you in any way, as you can't do much to cure excess headspace without spending (wasting) lots of money. The, by far, easiest and cheapest (actually free) way to handle any headspace concerns (which probably do not exist anyway) is to reload fired cases by neck sizing only. Then you will always have zero headspace, as the fired case fits the chamber precisely. The long-recoil action is very similar to a bolt action, as the fired cases are not yanked out of the chamber under pressure, therefore case body stretching is not an issue as is the situation for some gas-operated semiauto rifles. Of course, if you have multiple rifles of the same caliber, you must full-length resize for cartridge interchangeability. Or else segregate cases by rifle.

The hazards of excessive headspace are greatly overstated, and usually are inconsequential. It takes a LOT (as in HUGE) amount of excess headspace to cause a case failure on the first shot. The main concern results from performing full-length resizing of each case after every firing in an excess headspace chamber, as that works the brass greatly, and can result in a head separation upon firing after a few resizing cycles. All that is completely avoided by neck sizing only.

To neck size, just back off a full-length resizing die a bit (not much is required) so that only the neck is sized, not the body. You can determine that amount by trial-and-error and visual inspection.

Re: Project Research for a nice 32Rem and a "B" 35Rem

Posted: Tue Feb 26, 2013 11:11 pm
by Phyrbird

You make very valid points, in practical terms I agree. At the same time I'd like to set an example to be Sure. :ugeek: One issue will be with the 35R. I'm loading for a single shot pistol, a pump 760, and a pristine auto loader. I'd like to know which chamber is the tightest and size for it. I have an idea of what might work, but no parts just yet. I hope to do the right things for the right reasons.
There will be some case segregation as I follow an old Pet Loads article that details the strength of the 760 action and the benefits of freebore in that rifle. I won't be publishing my loads for that combination, they are warm. :twisted:
I have run a test with the 35R bolt and the 300Sav barrel, the bolt closes fine on the installed barrel. However, the boltface is just a little too small to chamber a 300Sav round. With my experience opening a bolt to fit 45-70 in a Siamese Mauser that is not a problem. And the design of the barrel is such that the bolt encloses only the rim of cartridge. It would not create pressure or headspace problems. With extra bolts available I can afford a test without altering the original.
Incidentally, our local small town gunsmith does all this kind of work. Look him up, Mike Ezell, Auburn Ky. You should see his compensators fitted to a barrel. Or rather you try to find the line where the comp meets the barrel, it's almost invisible. He has multiple awards for his match performance.


Re: Project Research for a nice 32Rem and a "B" 35Rem

Posted: Wed Feb 27, 2013 12:57 am
by DWalt
I can't say I am clear on your plans, but about the only sure way to get complete fired case interchangeability among different guns is to do a full resize each time. That's fine, but it does work the brass more. I personally neck size only for most of my bolt actions. I have three rifles in .30-'06, and I segregate cases to be reloaded for each by headstamp - Remington (Remington 700) , Winchester (Winchester Model 70), and Federal (Mossberg). One of these rifles, the Mossberg, has a negative headspace, as even factory loads have to be squeezed into the chamber a bit. It also shoots the best groups of the three. I follow the same procedure in both of my M81s in .300 Savage. One gets reformed 7.62 NATO military cases with LC headstamps exclusively, the other gets reformed Remington or Winchester .308 brass. I don't particularly like to use reformed Federal .308 brass as the neck case walls are too thick.

Re: Project Research for a nice 32Rem and a "B" 35Rem

Posted: Fri Mar 01, 2013 2:43 pm
by Phyrbird
Learn something new every day, 308 sizes to 300Sav :!: :!:
Any dimensional differences? Is there much trimming?