• The Shot You’ll Never Forget Giveaway - Enter To Win A Barrel From Rifle Barrel Blanks!

    Tell us about the best or most memorable shot you’ve ever taken. Contest ends June 13th and remember: subscribe for a better chance of winning!

    Join contest Subscribe

bump gauge?

Re: bump gauge?

Go Reneck, decap a 40sw case, decap your brass and use the 40 case as your HSG(head space gauge), it works just fine because the datum(measuring point) of the 308 family is .400, under no circumstances use Sinclairs HSG inserts, Hornady if you must pay for a HSG.
 
Re: bump gauge?

Thanks for the advice, I used my rifle for my 284, but I would like to actually take a measurement to see what I am actually doing. If that makes any sense, It is easier for me to learn more and understand what I am doing when I have a better way to quantify something.

Cobra, If you don't mind me asking what makes you say not to use Sinclair's

Thanks again for the help.

Walter
 
Re: bump gauge?

It's my understanding the Sinclair measures from the bottom of the case head to the shoulder, while the Hornady measures from the bottom of the case head to the shoulder datum line. Can anyone help me understand the advantages/disadvantages to these different measurements? Thanks.
Bob
 
Re: bump gauge?

I like the RCBS precision mic. The attachment that measures seating depth is worthless for such task but it will help you keep a handle on throat erosion.
 
Re: bump gauge?

I've found that all I need is a simple case gauge from either Dillon of Wilson.

For my .308 I use one from Dillon. I just check the fired case, look to see if it protrudes above the "Max" indicator and right there or slightly proud I just bump until the case head is between the Min/Max levels. Trying to use the Hornady or Sinclair attachments for a caliper can drive one nuts because they only measure at a single point. The case gauge more closely simulates a rifle chamber. Some shooters will even have one cut with the same reamer used to cut the chamber in their rifle. Tough to argue with those results and you don't have to mess with the whole rifle.
 
Re: bump gauge?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bob 964</div><div class="ubbcode-body">It's my understanding the Sinclair measures from the bottom of the case head to the shoulder, while the Hornady measures from the bottom of the case head to the shoulder datum line. Can anyone help me understand the advantages/disadvantages of these different measurements? Thanks.
Bob </div></div>

Before folks stop responding to Mr. Burke's question, I would like to raise this question one more time. Thanks.
 
Re: bump gauge?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bob 964</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bob 964</div><div class="ubbcode-body">It's my understanding the Sinclair measures from the bottom of the case head to the shoulder, while the Hornady measures from the bottom of the case head to the shoulder datum line. Can anyone help me understand the advantages/disadvantages of these different measurements? Thanks.
Bob </div></div>

Before folks stop responding to Mr. Burke's question, I would like to raise this question one more time. Thanks. </div></div>

Never mind... called Sinclair & talked to a reloading tech.
 
Re: bump gauge?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bob 964</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bob 964</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bob 964</div><div class="ubbcode-body">It's my understanding the Sinclair measures from the bottom of the case head to the shoulder, while the Hornady measures from the bottom of the case head to the shoulder datum line. Can anyone help me understand the advantages/disadvantages of these different measurements? Thanks.
Bob </div></div>

Before folks stop responding to Mr. Burke's question, I would like to raise this question one more time. Thanks. </div></div>

Never mind... called Sinclair & talked to a reloading tech. </div></div>

I was following this thread.. If you don't mind, what did the sinclair tech say?
 
Re: bump gauge?


It does not matter what the particular measurement is. It is more important to know where you are setting the shoulder relative to your rifle's chamber.

Find an empty case fired from your rifle that is too long to chamber without hard bolt closure. Use a case comparator tool like Possum Hollow / Hornady LnL or Sinclair comparator to measure that case several times to establish a good baseline measurement. Set your bump or full length die far enough out to not bump the shoulder and work your way down until it does bump the shoulder slightly. Chamber that sized case into your rifle and try to chamber the case. Is it still too tight? If so adjust your die just the very least bit lower. Size that same empty case again and try to chamber the empty case again. Do this until the empty case chambers with almost or no "crush" and then measure your empty case again using the same measurement methods used before sizing. This is where you want to set your resized cases at no longer no shorter for THIS rifle only!

Tips: Always measure empty cases that have been deprimed because a primer can and will change your shoulder and case length measurements. Trim to case length after neck sizing and bumping the case shoulder or full length resizing not before or you may change case length.
 
Re: bump gauge?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wburke2010</div><div class="ubbcode-body">I would also like to know what you were told by the tech, if you don't mind.

Walter </div></div>

It's essentially the difference between indexing off the entire shoulder and indexing off a single point (shoulder datum line). I decided to go with the Sinclair headspace gauge insert and comparator.