Your opinion on crush fit brass

[fguffey]

unless what I did doesn't mean anything!

What you have done made sense to someone.

gamestalker: What JimKirk said, slight

I checked your measurements, if I came up with those numbers I would say I had a short chamber. But: I am sure I would not be using the same methods and techniques you and JimK and gamestalker would be using.

I would use an absolute .375" diameter datum or a Wilson case gage with a feeler gage and straight edge. I would have measured the length of the case from the datumn/shoulder to the case head first before firing. I would record the length of the case in thousandths from the datum to the case head.

After firing I would measure the length of the case again from the datum/shoulder to the case head. The difference in length in thousandths would have given me the length of the chamber from the shoulder to the bolt face.

I wanted to see where the shoulders were on once fired brass

Once fired? With the different length cases I am not sure how you got all the shoulders to imprint.

When I want to know the length of the chamber from the shoulder to the bolt face I use 280 Remington cases. The 280 R case is longer than a 30/06 case from the shoulder to the case head by .051". I start by moving the shoulder back .041", that should give you a very snug fit if the bolt will close. After setting the shoulder back .041" and find the case will not allow the bolt to close I move the shoulder back an additional .005". Setting the shoulder back .046" will give you a case that is the same length as a go-gage length chamber.

I have one chamber that requires I adjust the die off the shell holder .014" when sizing 280 R cases for a 30/06 chamber. The chamber is .002" longer than a field reject length chamber.

F. Guffey

 

[FLIGHT762]

LTH, i use my Hornady headspace gage all the time to set up my sizing die. I don't think you can use it to compare any Saami dimensions though. It is not meant for that nor sized for that purpose.

Actually, you can compare a SAAMI dimension if you want to. All you need to do is take a SAAMI "Go" headspace gauge and measure it with the Hornady insert and note the dimension. You will not get the same reading as is on the "Go" gauge since the Hornady gauge inserts have a slight bevel (chamfer) on the edge of the gauge insert. As an example, I can take a 308 Winchester 1.630" "Go" gauge and measure the "Go" gauge. I get a reading of 1.622". It shows me my gauge insert has a .008" chamfer in it. The 1.622" reading is equal to 1.630" SAAMI minimum.

If I measure fired brass that has a reading of 1.625", it shows me I'm .003" over SAAMI minimum or @ 1.633".

I have a friendly local Gunsmith that allowed me to bring my calipers and gauges to his shop and he allowed me to measure several Go gauges so I could get SAAMI minimum readings on a few of my calibers. The readings give me a reference point to and from SAAMI dimensions.


Getting back on topic, O/P, As was suggested by a few members, take a few of your fired cases, measure them and set your F/L die to set (bump) the shoulder back .002"-003". Doing this you will have ammunition that will chamber easily and brass that will not be overworked and should last a long time.

 

[LTH]

The .280 trick makes since, I doubt I'll ever come across one without buying some.
My shooting range is the deer woods and I know no one that reloads personally.

If my smoked shoulders and measurements are anywhere close to being a short chamber , would this be uncommon ?

 

[fguffey]

would this be uncommon ?

Yes, you said you were using new factory ammo, you did not have trouble with closing the bolt on your factory ammo, that is normal.

I am the fan of transfers, standards, to determine the length of a case from the datum to the case head all I need is the datum. If my datum agrees with SAAMI's datum our measurements agree.

datum? Measure from, datum is not a line is a round hole. When using a comparator and I am comparing I make up datums, I just pick them out of the air? or list of eligible datums.

F. Guffey

 

[LTH]

Getting back on topic, O/P, As was suggested by a few members, take a few of your fired cases, measure them and set your F/L die to set (bump) the shoulder back .002"-003". Doing this you will have ammunition that will chamber easily and brass that will not be overworked and should last a long time.

Thanks Flight762, I'm gonna take this advice of the majority.

Though I do enjoy learning how things work !

 

[Clint M]

Keep in mind with factory chambers chances are the chamber is not cut/reamed concentric to the bore. This combined with a tight fitting case can/will cause the case to be pushed off center when chambered. Unless you have a known good chamber on a factory gun, or custom I would size the case enough for enough room as mentioned before .002"-.003" for a bolt action factory round should give good results with brass life, and accuracy, easy loading.

 

[LTH]

d. Unless you have a known good chamber on a factory gun, or custom

I don't know if it does or not.
It shoots factory ammo pretty good.

 

[Clint M]

LTH it's dang nice to have a gun you can shoot factory ammo in with good results.

If your chamber is off some (not really your chamber lol just an example) if you do not size brass enough meaning a hard to moderate bolt close then you are performing some of the sizing with your bolt. The case will have a bow in it which would be hard to measure the two problems if you index your brass to chamber then each firing it becomes worse. If you do not index it then each firing you will have a wobble like to your brass as it's fitted exactly to your chamber I hope this makes sense.

Other ways to fix this problem of less than perfect chambers. Partial neck size that leaves a small area of the neck to center your case, you could even combine this with a body die and size the case, bumping the shoulders back .002" for easy chambering. Use Lee collet die, I actually paired this with a Redding body die years ago people on some forums gave me a hard time, however it works and by far produces the best accuracy with factory guns, semi customs that I have owned all while being affordable.

I'm sure other tricks will also work, I hope I didn't stray to far from your post. There is a good article on web about factory chambers or less than perfect chambers and banana shape brass if you can find it's worth a read. All that said you may have found the best way for your chamber already/rifle already.