257 Robert's necked down.is the 6mm Remington just the 7x57 necked down to 6mm? if so I have plenty of cases to run thru 6mm dies and thus a new savage build will be in the works!!
257 Robert's necked down.is the 6mm Remington just the 7x57 necked down to 6mm? if so I have plenty of cases to run thru 6mm dies and thus a new savage build will be in the works!!
Right, right, and right.Amplifying on my previous post on neck wall thickening:
The neck wall of nearly any factory case is tapered - thinnest at the case mouth, thickest approaching the shoulder junction. When you neck turn, you are largely mitigating this by rendering the neck wall nearly uniform in thickness along its length. If you start with a 7x57 case (neck not turned) and form it in a 6mm Rem FL die, you are creating a case with a significantly enhanced constriction at the base of the neck (near the shoulder junction.)
I reformed 7x57 first in a 257 Roberts FL die, then in a 6mm Rem FL die. Then I used pin gages to probe the neck ID. My notes say:
Gage Depth
0.231 100%
0.235 50%
Translation: A 0.231 gage was the largest that entered the neck past the neck/shoulder junction. A 0.235 gage only entered ~halfway into the neck. One may extrapolate that the ID at the case mouth is ~ 0.239 (assuming a uniform wall taper.)
The OD of the neck after sizing in 6mm Rem FL die was 0.269. So (extrapolating some more) the neck wall at the case mouth was likely ~0.015 thick, but near the shoulder junction 0.019 thick.
I leave it as an exercise for the reader to deduce the implication of this these neck wall dimensions on subsequent bullet seating and neck sizing. But I reiterate you should strongly consider turning the necks of the 7x57 cases before forming into 6mm Rem. This will reduce the stress associated with sizing the necks down that far, and avoid carrying along and enhancing the original doughn... er, thicker region near the shoulder junction.
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I neck turn everything I own if just to make sure the case neck is uniform from the shoulder to end of the neck,,, then i check for wall thickness!!Amplifying on my previous post on neck wall thickening:
The neck wall of nearly any factory case is tapered - thinnest at the case mouth, thickest approaching the shoulder junction. When you neck turn, you are largely mitigating this by rendering the neck wall nearly uniform in thickness along its length. If you start with a 7x57 case (neck not turned) and form it in a 6mm Rem FL die, you are creating a case with a significantly enhanced constriction at the base of the neck (near the shoulder junction.)
I reformed 7x57 first in a 257 Roberts FL die, then in a 6mm Rem FL die. Then I used pin gages to probe the neck ID. My notes say:
Gage Depth
0.231 100%
0.235 50%
Translation: A 0.231 gage was the largest that entered the neck past the neck/shoulder junction. A 0.235 gage only entered ~halfway into the neck. One may extrapolate that the ID at the case mouth is ~ 0.239 (assuming a uniform wall taper.)
The OD of the neck after sizing in 6mm Rem FL die was 0.269. So (extrapolating some more) the neck wall at the case mouth was likely ~0.015 thick, but near the shoulder junction 0.019 thick.
I leave it as an exercise for the reader to deduce the implication of this these neck wall dimensions on subsequent bullet seating and neck sizing. But I reiterate you should strongly consider turning the necks of the 7x57 cases before forming into 6mm Rem. This will reduce the stress associated with sizing the necks down that far, and avoid carrying along and enhancing the original doughn... er, thicker region near the shoulder junction.
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Fair enough. It would be informative, however, to know your chamber neck dimension, bullet used, and depth it is seated to.I've got a 6mmAI and I just neck down the 7x57 brass. Works perfectly.
Q. what powder / brass combo is your pet load and did you run this through a chrony for ES / SD information?...what bbl length U have ?I use my Rem. model 700, chambered in 6mm Rem for hunting feral hogs. I have killed almost 200 of them in the last 3 years. It is my favorite rifle for hunting. It is a 9 twist and loves the 100 gr. Nosler Partition bullet.
Build it and you will love it!
Q. what powder / brass combo is your pet load and did you run this through a chrony for ES / SD information?...what bbl length U have ?
Reloader 23/Norma brass
Averaging 3,047 fps
22" barrel length.
SD= 5.436
ES= 18
+1 You can't go wrong with RWS brass in the 6mm Rem!!All that i have ever used is 7x57 rws brass in mine
Using RL23 with 90gr bullet....what amount of powder might be a good starting point
PERFECT...thank-you! My RL23 is on order and arriving next week. Looking forward to those low ES and SD results.Found this- it should help
Ave