Trouble chambering 7x57 Mauser

[Tackleberry41]

Says he was using factory ammo and tried more than one. Considering it worked fine for one barrel but not another, I would go with the reamer. I know they are not cheap so a company would try to rent them as long as possible. Not like they test them after ever rental. No telling what the last renter did with it. But a new 357 sig reamer still had to take off metal the rental did not.

[7x57Mauser]

Says he was using factory ammo and tried more than one. Considering it worked fine for one barrel but not another, I would go with the reamer. I know they are not cheap so a company would try to rent them as long as possible. Not like they test them after ever rental. No telling what the last renter did with it. But a new 357 sig reamer still had to take off metal the rental did not.

Yeah, it looked fine, and measured about .002" larger than a new factory cartridge all along its length. I've never measured a reamer before, so I don't have anything to compare that to. I just know the first one worked perfectly and the second didn't.

I called 4d Reamers once and sent them 2 emails, but have heard nothing. Don't really expect to at this point.

I think my plan is to buy my own reamer since I really like 7x57 and will likely continue to work with that caliber. I'll carefully recut the 2nd barrel I just did (without going any deeper) and see if that fixes the problem. Then I'll set aside that barrel I went too deep on. If I ever shoot one of my barrels out and need it, I can set it back a hair and rechamber.

[Tackleberry41]

I never heard from 4d on the 357 reamer either. I doubt it takes much of a bubba to screw up a reamer, nor do I expect much in way of effort from the rental company in this day and age. They may have several complaints about the reamer and just shrug their shoulders. Anymore I buy a reamer, use it then sell it. Vs getting another bad rental. Whatever I saved renting, I blew fixing it.

[2152hq]

"....All had excessive headspace when I got them (meaning, they'd close on a nogo gauge. I don't have a field gauge.)...."

(The bolt) closing on a NoGo gauge does not necessarily mean that the rifle has excess headspace.

That can only be confirmed with the Field gauge.

The GO gauge is the minimim spec of the headspace dimension
The NOGO is an intermediate dimension. One which is generally accepted as the best for all around use with factory ammunition.
The Field is absolute limit in dimension/spec. Anything beyond the FIELD GAUGE(closing on the Field Gauge) is considered Excess Headspace.

We like the action to feel some resistance with the use of the NOGO gauge. That puts the chamber headspace dimension in the middle on the spec somewhere.
You like to feel bolt resistance when using the NoGo gauge,,a comforting feeling. That's where we like them to land!

But closing on the NoGo is not excessive headspace necessarily.
Only a Field gauge can confirm out of spec/excess HS ,,that by closing all the way and with no resistance on that Field gauge.

[ulav8r]

The field is considered excessive headspace except for mailtary rifles during war time. Otherwise, nogo should be considered the allowable maximum. If the bolt closes on a go gauge it should accept any factory ammo. It might not accept dirty ammo delivered under battle field conditions.

[2152hq]

Yes..'closing all the way' on a Field is excessive headspace.
But if the bolt only partially on a Field,,it is not excessive headspace. The Field gauge is made to the maximum limit allowable.

If the bolt does not close on FIELD, the rifle is still in spec. It's at the far end of the allowable spec. But still within it.

[ulav8r]

Yes..'closing all the way' on a Field is excessive headspace.
But if the bolt only partially on a Field,,it is not excessive headspace. The Field gauge is made to the maximum limit allowable.

If the bolt does not close on FIELD, the rifle is still in spec. It's at the far end of the allowable spec. But still within it.

Still wrong. Field gauges were developed by the military to check rifles in the field to determine if they needed to taken out of service.

The following is taken from Pacific Tool and Gauge web site.
"1: GO: Corresponds to the minimum chamber dimensions. If a rifle closes on a GO gauge, the chamber will accept ammunition that is made to SAAMI’s maximum specifications. The GO gauge is essential for checking a newly-reamed chamber in order to ensure a tight, accurate and safe chamber that will accept SAAMI maximum ammo. Although the GO gauge is necessary for a gunsmith or armorer, it usually has fewer applications for the collector or surplus firearms purchaser.

2: NO-GO: Corresponds to the maximum headspace Forster recommends for gunsmiths chambering new, bolt action rifles. This is NOT a SAAMI-maximum measurement. If a rifle closes on a NO-GO gauge, it may still be within SAAMI specifications or it may have excessive headspace. To determine if there is excessive headspace, the chamber should then be checked with a FIELD gauge. The NO-GO gauge is a valuable tool for checking a newly-reamed chamber in order to ensure a tight and accurate chamber.

3: FIELD: Corresponds to the longest safe headspace. If a rifle closes on a FIELD gauge, its chamber is dangerously close to, or longer than, SAAMI’s specified maximum chamber size. If chamber headspace is excessive, the gun should be taken out of service until it has been inspected and repaired by a competent gunsmith. FIELD gauges are slightly shorter than the SAAMI maximum in order to give a small safety margin."

Read the description closely. Especially note that accepting a No Go may indicate excessive headspace.