03 headspace issue

[mtbugle]

I was shooting some verification loads last weekend in two of my sportarized o3's. I noticed one starting to push primers back out of brass a little. So I looked her over when got home. I put some black felt tip on lugs to pattern test and only saw a sliver of contact on one lug.(great) So I looked closer at the lugs on the bolt and they look like just rough cut to length. There is deep grinding or cuting marks and doesnt look like any attempt to smooth out prior to bolt being parkerized. So I am thinking I could just use file and sandpaper to smooth as close to flat as possible then keep shortning lug still making contact till other is also, then lap for final good patterning of contact. Then have barrel set back a thread. Does this sound reasonable to attempt without having the fancy lathes and assuming bolt lugs are hardened throughout not just on surface. The bolt body is marked B&S if that makes any difference. I appreciate any comments from those more experienced with these and am not afraid to do as much as I can of it at home.
Thanks Don

[Frank46]

Sportsmans guide has new 03a3 bolts complete with all parts. Think $40.00. And you might get a couple headspace guages. If you are shooting your own reloads check to see if you are excessively resizing your cases. I had an 03a3 rebarreled years ago and the gunsmith did such a good job that the origional bolt and a 03a4 bolt both headspace just find.
Great rifles. Frank

[mtbugle]

Thanks Frank for the reply and heads up on source for new if I need to go that route. I am still hoping that some of the oldschool smiths will chime in on my hardness concerns to verify I can work down the old lugs. I am guessing that when this modification was popular that the after market bolot bodies were cut long with the expectation the smith would work them down to size. But want an educated or experienced reality check before beginning work(ie messing up).
Thanks Don.

[gunnut69]

The springfields were not casehardened at leaast not the '03A3's. Mausers were fairly mild steel and were hardened thru a casehardening process only on the outside and then in areas where it was needed. Lap a mauser too much and the skin will be penetrated or at least weakened on the lug seats and the result can be 'printing' or creating a dent on the lug seat in the receiver which effectively ruins the receiver. It's likely the bolt lugs are as hard as woodpecker lips and are just a product of wartime expediancy. The primer extrusion of a round is not always a headspace problem. Lapping would remove the roughness but would also lengthen the headspace. Remember headspace is the length from the datem line to the bolt face. The datem line's position is different on various types of cases. On a rimless cartridge such as the 30-06 it is located on the sloping shoulder or the bottlenecked round. On a belted magnum round such as the 7mm RemMag it is located on the front face of the belt itself. It is difficult to measure accurately without a guage and with the guage it is quite simple. Using a cartridge case and shims only measures that round in the chamber in question and even that can be altered by a bit of force on the bolt handle(causes the case demensions to change). You must measure the headspace to ensure the rifle is in speck. If it is found to be so then the barrel can be removed and the bolt lapped and the barrel reset and re-headspaced.. Remember when lapping a bolt to a receiver both are altered and pressure should be applied evenly and without spring tension. If the tension is applied by a spring the high spots and the low spots will both be polished making for smoothness but uneven change in dimensions. The rigid tension will apply force only on the high spots and they will be removed. When the high spots are gone the entier surface will be polished.. It is best done with the barrel out.

[mtbugle]

Thanks gunnut69. I think the bolt is an aftermarked as looks like turndown from start not bent or rewelded, and stamped B&S. I am sure will need a good couple hundreds to clean up, so a lot of removal before lapping. Thanks for the insight of lugs themselves not just surface hardened.
Thanks Don.
Also thinking file will probably not touch this hard of metal? Probably all stone and lapping material to take it down?
Too ensure I understand correctly on the Mausers the action is surface hardened, but bolt lugs are still all hard, not surface hardened on bolt?

[gunnut69]

That is correct on mauser bolt hardness. To clean up the lugs on your springfield a lathe can be used with carbide tooling and a rigid setup but I'm a poor machinist soooooo.. A grinder used with the lathe to turn the bolt between centers would even and level, polishing would be best done in the receiver.. Also you must remember the lack of engagement may be at least partly the responsibility of the lug abutments in the receiver so truling the receiver is also a likely need.. This too can be done in the lathe.. Go very lightly.. An engagement of 60% or so on each lug would be fine. After the action is realigned the barrel will need setting back and headspacing. Remember when doing this sort of thing the bearing surfaces(rear of lugs and lug abutments) must be kept aligned with one another. This blueprinting of the action is tricky work but will make for a slick rifle.

[mtbugle]

Thanks again gunnut. I don't have a lathe, but for the barrel turning I have had good succes previously turning by drill useing a 1/4 threaded rod with some electrical tape to size up and protect rifling, supported between couple of old bearings mounted on my work bench. That should work for cutting new sholder, and I will just have to try to freehadn the thread part, or will cut to bottom of threading if too much trouble. The bolt may be a little harder, possibly can find a way to get it chucked in my drill press? I am confident this job is going to be doable. Mentioning blue printing of action. What else would be good to slick up while I am in it? or a good site with step instructions?
Thanks again, Don.

[gunnut69]

The only reason for cutting off 1 thread is to facilitate the return of the sights to the top of the rifle with the sights nice and verticle. Cutting the barrel shank off allows the bolt room to close and so can be measured from the front of the receiver ring. If doing all this, machining the front of the receiver ring true to the axis of the action would be good..but without a lathe that is not really feasible. Also cutting the shoulder using a drill may work and may not. At the least the shoulder won't be sqare to the central axis of the action.. For these processes to work I highly recommend a lathe.. You will also need a set of headspace guages(at least 'go' and 'no go'), a chamber reamer and the correct action wrench and barrel vice to take down the barreled action.. Also a micrometer and (or) a dial calipher to make the precise measurements needed for these operations.

[John Traveler]

I second gunnut69's suggestion that you have access to a lathe and the ability to use it before attempting modifications to the barrel.

Turning the barrel shoulder to advance the barrel by one full thread also requires that you cut forward the breech, recut the feed cone, and the extractor clearance.  A chamber reamer and headspace gages will also be required.

As an alternate solution, may I suggest that you obtain several bolts and a set of headspace gages to try and selectively fit a bolt to reduce your excessive headspace?  That should be a cheaper fix than cobbling up the rifle itself.

Find yourself a friendly gunsmith or a parts supply house and explain your needs.  You want to buy a replacement bolt, but you want to selectively fit a good bolt to eliminate your excessive headspace problems.  Ask for a refun policy or a deposit to cover the several bolts you need to try out.

[John Traveler]

I've encountered several M1903 bolts marked B&S and am sure that they are original WWII surplus and not aftermarket products.

B&S signifies Brown and Sharp, an old, extablished precision machine tool company.  In the rush of wartime production, they, or anyone else, is capable of making a product with rough machined surfaces.

Actually, for the very limited demand for sporterized M1903 Springfield bolts, I can't see anyone making aftermarket bolts.  There were simply too many of the genuine GI surplus articles available for low prices during the time period (1945-1970s) when sporterizing the M1903 Springfield was a popular activity.

[mtbugle]

Thanks for the insight John. I am evaluating my options.
Thanks Don.