I am placing an order with clymer for a 7x57 and a 9.3x62 reamer. These are my first two removable pilot reamers, and I am in need of some information. Ideally I would have the barrels that would be chambered with these reamers on hand and order the bushings according to bore size. Unfortunately I don't so I need to know what the standard bore size for 9.3 and 7mm actually are, then I can order bushings accordingly.

Thanks

Thomas,
You need to get your barrel and see what it actually is. There are small variations between manufacturers and the pilots are built with a range of sizes. You can just buy an assortment +/- the bore size

It looks like the barrels are still at least a month or two away, and I would like to order the reamers right away so that they might be here by the time the barrels arrive. I will probably just buy an assortment of bushings +/- the bore size.

You can ask your barrel maker the size of his finished bore, but most purchase a set of bushings per bore size. Until the barrle is finished lapped, the actual bore size could vary a little bit. But, you are doing the right thing by getting piloted reamers. Get the recommendation from the barrel guy for bore size, get the reamers, pilots and barrels in hand, and if need be, the reamer maker should be able to send you a bushing in the mail the same day you call if the ones you get don't fit right.

Thomas,
JGS will sell you a set of bushings (9) for a caliber that will cover your needs and you will have them for future projects. They are not cheap ($90.00) but you only need to purchase once and they do not require feeding. Jim

You could order barrels and pin gages now and reamers now and pilots after you measure the bore with pin gages.



Pilots are tiny, off the shelf, and will ship fast to you.















MSC pdf download of a catalog page with $1.65 pin gages

The object to ordering a removable pilot reamer is so the pilot will exactly fit the bore. If you want to order a reamer without having the bore in hand and already gauged. you might as well have a fixed pilot reamer at approximately half the price. The chances are just as good that the fixed pilot will be as perfect a fit as any removable pilot you order, if you don't KNOW what size your bore is.



I think one of the fellas ahead of me gave you the right answer. Order barrels, and removable pilot reamer now. When you get barrel(s) and have reamer(s) in hand, then you can either pin-gauge or "slug" your bore(s) to find out what exact size pilot you need.



For myself, I prefer to have a variety of pilots on hand, with not more than .0002" difference betwen each one. I personally find the best way to gauge the size needed is to put the pilot(s) on the reamer and very carefully check the fit with the pilot(s) themselves. "Feel" is an important "tool" in this process for me, if I want a perfect fit.



I personally don't believe asking the barrel maker what size his barrels are is an approach I would use. My experience is that some popular barrel makers, including some VERY big name benchrest barrel makers, haven't got a clue what size any specific one of their individual barrels will be when finished. While it is true that their barrels usually are consistently within .0002" from one end to the other, with at least a couple of makers there is no predicting closer than .002" (two thousandths, not two 10,000ths) what actual land diameter that will consistently be.



One, for instance, from whom my friends and I tried ordering .30 barrels, supplied barrels ranging all the way in bore from .3000" to .3020" land diameters. We don't use his barrels any more precisely because of that. They were good, accurate shooters, and were consistent from end to end, but we got tired of making a new pilot for almost every one of his barrels we got. And, although his barrels were the most varied we have encounted, EVERY barrel maker has tolerances in the sizes they feel appropriate to send out the door.



So, I think the straight advice is, get the barrel(s) first, decide what size pilot you actually need/want, and then order the appropriate pilot. When you order the actual reamer on which the pilot is to fit doesn't matter too much.



Patience will be a real virtue in this ordering process, just as it is in the actual chambering work.



BTW, though this comment may draw a fair amount of flak, I believe that unless you are building a benchrest rifle, your pilot doesn't normally HAVE to be an exact fit. There have been many, many excellent hunting rifles built with fixed pilot reamers, by careful, skilled, use of the tools involved.



Good luck, and have fun....



AC