Sizing die adjustment

[john 800]

I had not thought about adjusting sizing does in years, haven’t gotten new dies or new rifles so everything stayed where it was when I set it up years earlier, a few weeks ago I had to replace a 308 sizing die because somehow it started scratching cases. Bought a new hornady die and watched some videos and read a little to refresh my memory and I ended up using a sharpie on the shoulder and played around untill the sharpie was just barely scuffed when I would chamber a sized round.
I do not have a comparator to measure shoulder bump, one of the videos, (Eric Cortina) mentioned 2 thousandths shoulder bump as a starting point. I am not shooting competitively, nor long range, but I would like the best accuracy and case life I can get. Is it worth measuring? Is light contact on ink on the shoulder of a case pushing being “not sized enough” for hunting rounds?
I know competetive, BR ect guys get very precise with cases and I am just wondering if there is enough to be gained for me to pay attention to it or if I will never notice a difference.
What do you think? Is this good enough with the ink or is there a better way?

 

[rijndael]

... I would like the best accuracy and case life I can get. Is it worth measuring?

I would get the proper tools.

 

[BoydAllen]

Many years ago, when I got my comparitor, I suggested that an older friend get one. He has built his own rifles, doing the barreling and bedding, and shot them very well. His reply was something to the effect of "Why do I need one of those since I have been loading for years without one?", so I challenged him to a test. I had him "unset" and reset one of his sizing dies several times and bring me one case for each setting to measure with my gauge. The results were all over the place. He went home and built himself a gauge similar to the ones that come with Harrell's dies. I cannot tell you if buying a tool will do anything for you, but my prejudice is in favor of being able to measure things.

 

[Straightshooter1]

I had not thought about adjusting sizing does in years, haven’t gotten new dies or new rifles so everything stayed where it was when I set it up years earlier, a few weeks ago I had to replace a 308 sizing die because somehow it started scratching cases. Bought a new hornady die and watched some videos and read a little to refresh my memory and I ended up using a sharpie on the shoulder and played around untill the sharpie was just barely scuffed when I would chamber a sized round.
I do not have a comparator to measure shoulder bump, one of the videos, (Eric Cortina) mentioned 2 thousandths shoulder bump as a starting point. I am not shooting competitively, nor long range, but I would like the best accuracy and case life I can get. Is it worth measuring? Is light contact on ink on the shoulder of a case pushing being “not sized enough” for hunting rounds?
I know competetive, BR ect guys get very precise with cases and I am just wondering if there is enough to be gained for me to pay attention to it or if I will never notice a difference.
What do you think? Is this good enough with the ink or is there a better way?

A house can be built without the use of measuring tools. But is that the kind of house you'd be satisfied with?

 

[Fast14riot]

You can use a 38/357 case as a inexpensive comparator for measuring shoulder bump on 308 cases. Deprime it and be sure its round, always use the same case, too.

 

[Jdne5b]

Technically you can use the method here without a gauge. If you wanted to keep track of it, use a 38/357 case like described above.

Scroll down to the Sizing Brass video.

Videos | wheeleraccuracy

www.wheeleraccuracy.com

 

[fatelvis]

Do yourself a favor and buy one of Whidden's click adjustable lock rings. It makes adjusting your die a snap!

 

[JayHHI6818]

I bought a used set of Whidden dies and they come with this bump gauge. Works great.

Shoulder Bump Gauge - Whidden Gunworks

The Whidden Gunworks shoulder bump gauge enables you to adjust your sizing die to the desired measurement. The bump gauge is attached to your calipers with a set screw and determines the measurement from the base to the shoulder of the case. We now offer a Thumbscrew Pack that will fit the...

www.whiddengunworks.com

 

[jepp2]

Is light contact on ink on the shoulder of a case pushing being “not sized enough” for hunting rounds?

Maybe, until the one day you chamber a round for that big buck. And the round you just chambered happens to have some kind of foreign material on the shoulder (picked it up somewhere) and all of a sudden you can't close that bolt and shoot that big buck. Or maybe you didn't quite enough sizing lube on that case and the shoulder didn't get back as much as your other cases.

I probably run with less shoulder setback than most. I want 0.001" from bolt contact. But what I call bolt contact is what you are probably sizing to. Maybe even more. And I know my lube process applies the lube extremely uniformly so my measurement on cases are less than 0.001" variation. I want the round to chamber without even thinking about contact. And the only way I can run this close is to measure and know the variation in my process.

As others have suggested, having the proper tool to measure is important. And yes, you can use lots of things, but I want to use the tool that has the same diameter as the datum line for the case I am sizing.

 

[JMayo]

If i were just hunting and playing I'd take a fired case and sneak up on a light bolt close and go with it. Ppl have been just neck sizing hunting rounds longer than I've been alive.

 

[hoz53]

Maybe, until the one day you chamber a round for that big buck. And the round you just chambered happens to have some kind of foreign material on the shoulder (picked it up somewhere) and all of a sudden you can't close that bolt and shoot that big buck. Or maybe you didn't quite enough sizing lube on that case and the shoulder didn't get back as much as your other cases.

I probably run with less shoulder setback than most. I want 0.001" from bolt contact. But what I call bolt contact is what you are probably sizing to. Maybe even more. And I know my lube process applies the lube extremely uniformly so my measurement on cases are less than 0.001" variation. I want the round to chamber without even thinking about contact. And the only way I can run this close is to measure and know the variation in my process.

As others have suggested, having the proper tool to measure is important. And yes, you can use lots of things, but I want to use the tool that has the same diameter as the datum line for the case I am sizing.

id like to use the tool that has datum diameter to Jepp. What tool do you use? I have
sinclair set i use and hornady in the tool box

 

[jepp2]

What tool do you use?

I acquired this in a package deal I purchased. I didn't take it too seriously until I started using it some. I dropped my go gauge into it and tightened it down just to see how close it would read. From then on I was impressed. With the right touch and knowledge of your rifle, a relative gauge like the Hornady headspace comparator can give adequate results.

 

[Kracken McGraw]

I acquired this in a package deal I purchased. I didn't take it too seriously until I started using it some. I dropped my go gauge into it and tightened it down just to see how close it would read. From then on I was impressed. With the right touch and knowledge of your rifle, a relative gauge like the Hornady headspace comparator can give adequate results.

View attachment 1296366View attachment 1296367View attachment 1296368

Curious, what does a fired case read on the measurement before you size it?

 

[hoz53]

I acquired this in a package deal I purchased. I didn't take it too seriously until I started using it some. I dropped my go gauge into it and tightened it down just to see how close it would read. From then on I was impressed. With the right touch and knowledge of your rifle, a relative gauge like the Hornady headspace comparator can give adequate results.

View attachment 1296366View attachment 1296367View attachment 1296368

oh so you drop each case in there and screw top on. i have the sinclair which works fine for me but it does just give you a relative measurement. i do sometimes just measure a headspace gauge with it to know where i am at. thanks for the info ill look into the whidden one

 

[hoz53]

Curious, what does a fired case read on the measurement before you size it?

that would depend on the chamber wouldnt it?

 

[Kracken McGraw]

that would depend on the chamber wouldnt it?

Yes I was just curious where his case measured between the go and no go on that gauge is all.

 

[hoz53]

Yes I was just curious where his case measured between the go and no go on that gauge is all.

i see— looking at that gauge a little more i guess the marks are .001 and it shows nogo at
.010. it would be interesting to me what it shows a nogo gauge measurement. that wouldnt really matter to me though. this gage may be more consistent than i am with calipers- that would be its value to me.

 

[Ned Ludd]

John - my advice would also be to obtain the necessary tools and measure.

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A modestly-priced set such as listed above will cost under $70.00, and can also be used for making a variety of other measurements, especially if you add in a few bullet comparator inserts as you go along.

 

[Sebrock]

I had not thought about adjusting sizing does in years, haven’t gotten new dies or new rifles so everything stayed where it was when I set it up years earlier, a few weeks ago I had to replace a 308 sizing die because somehow it started scratching cases. Bought a new hornady die and watched some videos and read a little to refresh my memory and I ended up using a sharpie on the shoulder and played around untill the sharpie was just barely scuffed when I would chamber a sized round.
I do not have a comparator to measure shoulder bump, one of the videos, (Eric Cortina) mentioned 2 thousandths shoulder bump as a starting point. I am not shooting competitively, nor long range, but I would like the best accuracy and case life I can get. Is it worth measuring? Is light contact on ink on the shoulder of a case pushing being “not sized enough” for hunting rounds?
I know competetive, BR ect guys get very precise with cases and I am just wondering if there is enough to be gained for me to pay attention to it or if I will never notice a difference.
What do you think? Is this good enough with the ink or is there a better way?

You can buy a Redding shellholder set and then change the shellholder until your sized brass chambers in the rifle with a normal feeling bolt lift (you probably want to remove the firing pin and extractor depending on your action but not totally necessary). This way you are sizing brass specifically to your chamber and not for a certain amount of bump. If you do not want to buy anything, then just start long on the sizing and make micro turns on the die until you get the round to fit in the same way as the shell holder set - here you might actually get minute enough adjustments that you will feel the difference in the bolt. When you get to a setting try with a few other pieces of brass. Its not so much about accuracy but knowing your rifle will chamber and that you didnt size so much that you are overworking your brass.

 

[jepp2]

Curious, what does a fired case read on the measurement before you size it?

It varies. New cases normally are shorter by about 0.001" if they are close to the correct length. If they are shorter, they grow by about 2+ thousandths. For brass that has been fired and sized, the normal growth is about 0.001".

Those dimensions are from the starting case head to datum length. Not necessarily the go gauge length.