H&R 270 chamber

[Mike in tx]

The min spec neck is what I am thinking right now. I will recheck the gauges but I had a friend with me when I tested it. I am measuring the cases NOW. Length of fired case 2.532.5. Unfired case 2.529.5. Lyman 49th max is 2.540. Shoulder is 1.948 on both the factory ammo and the fired case. The rim dimensions are .4515 for for the unfired and .4516 for the fired cases. Just ahead of the rim on the body the unfired case is .4114 and fired case is .4115 with multiple measurements with a mic. Shoulder mics out at .4215 on the factory case and .4217 on the fired case. The cases measured are R-P head stamp.

The primers are not abnormal to my eye; poor that they may be. They measure out within .0095 below the head for the factory ammo and .007 on the fired case. There are no marks on the case heads.

These are multiple measurements and appear to be within specs. I realize that there is spring back of the case on firing. I rechecked the chamber with the no go gauge and it chambered. I do not have any unsized cases from the Mossberg. I do have some cerro and will do a chamber cast when it cools down and I have the time as I am nosing around for a new job.

Everything contradicts and I am puzzled. I will check with the fellows on Grey Beard. Nothing makes sense at this time. The brass seems to be within specs. The rifle locks up well and does not flop open on shooting.

[Mike in tx]

The folks on Grey Beard think that it is a minimum chamber.

[versifier]

Well, it can't be a minimum chamber if the NO GO went in. That's for certain. Only in math can the inside be bigger than the outside. And your measurements show there is not an issue with the body diameter, at least not an obvious one.

But headspace gauges tell you nothing about the neck. As I said, I have seen minimum neck diameter more than once when trying fatter cast bullets rifles that had no problems with normal diameter jacketed, as well as in the rifle with the match chamber I mentioned. That's why I asked about how far it went in before stopping. I'm assuming the binding is happening at the neck only.

Mind you, it is possible (if unlikely) that the case is binding below the shoulder, but I would think there would be other obvious signs of it. To eliminate that from the possibles list, you could try coloring the top half of a case you know doesn't fit with a dark marker and inserting it very gently until it stops to see if there is any ruboff on the case body, and exactly where it is binding up.

[Mike in tx]

I miswrote, it was minimum neck that I was referring to. I will ask Jim (stepson) if he has any of the ammo left and if so will try what you suggested.

[Mike in tx]

I found some of the rounds loaded for the Mossberg. The shoulder sits 1.976 compared to 1.948 for the cases fired. The case length is 2.555 compared to the fired case of 2.5295. IIRC I only necked sized these cases as that is my habit for cases to be fired in the same rifle. The reason I bring this up is that I took your advice and colored a case. There were scuff marks on the shoulder and not the neck. Conclusion, reloading practice and outsized chambers in both rifles. I will check Jim's rifle and if need be will reset his barrel. Perhaps it will make it shoot better though it shoots 1.5 MOA. Any comments will be appreciated. As a side note I am NOT going to change the Handi at all.

[Mike in tx]

The shoulder for the Mossberg ammo is 1.976 compared to 1.948 for the Handi fired case. The Mossberg case is 2.555 case length compared to 2.5295 for the fired Handi case. This is for clarification.

[versifier]

Both rifles have overlong chambers? Wow, you won't see that very often in anything but a .303Brit or a Moisin. (SMLE's had interchangeable length bolt heads because there was so much variation in them depending on when and where they were made, the Russians didn't seem to care as long as they went bang every time when it was really cold.) But maybe QC in factory rifles has been slipping. So you'll just need a separate FL sizer for each rifle and keep their brass segregated too. Different color plastic ammo boxes for each should help avoid confusion. That's how I keep them straight with mine and my bro's .308's. I've been loading for both of them for over 30yrs with no problems. (In an emergency, I can shoot his NS sized rounds in my Rem788bolt, but he can't chamber mine reliably in his Win88 lever. Not that I would need to, but I was explaining about neck sizing to him and why I do it one day and we got curious and checked it out.)

IIRC, the Mossberg has a barrel nut like Savages (and Sam's Mausers)? That makes things easier to reset headspace. I doubt resetting it will affect its accuracy level, just its brass life, though it may change its POI a bit. But I would take a close look at that crown with a good magnifier and see if it is even and without any burrs, I know from all the milsurps I play with sometimes a twist or two with a crowning tool really tightens up the groups when I can't get the accuracy level I think the rifle is capable of.

Not much you could do to the H&R anyway, treat the brass like a wildcat (by that I mean be careful not to set the shoulder back any more than necessary when FL sizing to minimize stretching and prevent head separations, same as you would with a rimmed or belted case). With an overlong chamber it is, in effect, a wildcat case that uses the same loading data as its parent. I would think you ought to be able to neck size its own brass for it, and if the neck sizer is a collet die you should be able to use it for both rifles (same press & shell holder) without readjusting.

[Mike in tx]

Do you hear from Sam? I miss his advice and information.

[versifier]

Sam can be found on the FaceBook Reload Bench Group. https://www.facebook.com/groups/229625523718210/ An interesting group he and Aaron have put together.