Hey all, been lurking here a while and finally signed up to post.

New to reloading. Bought a press a year ago and am trying to get as much info. as possible before I do too much.

I have been troubled lately about this concept of correctly headsizing my casings. Not exactly sure how to get the correct amount of shoulder knock back.

I bought a hornady headspace gauge and have been doing some measuring of my shot casings and comparing them to new casings, but I am a little concerned about having the correct amount of headspace when I resize my casings.

I noticed in my reloading books that the Lee reloading manual has a headspace measurement for each caliber in its reference materials. Is this the number I should be using?

Any thoughts or tips about getting the right headspace number????

Also, I would like to neck resize some cases to see about increasing my accuracy. How do I ensure the headspace of the shell will be correct when neck resizing??

Thanks for the advice all. I will be leaving town and not getting back until tomorrow afternoon so don't think I posted and dashed.

Trying to get all the information I can before diving into this too far. I am adhering the old advice of a little knowledge can be dangerous....

Do they fit in the chamber with out having a hard closeing bolt. if they do that after neck sizing they should be right. One has to be careful that one doesn't bump the shoulders back. But if one dose that to hard you well have a ring and well not be able to chamber them.

I personnaly use the bolt closing as a very good indicator as the proper shell fit. If bolts close with no trouble they are most likely sized properly. To hard on closing most lilely means something is wrong.

Mark,

Welcome to the dark side! Seriously, handloading is a great pursuit and the learning never stops. Obviously you are paying attention to the details, and that is a good thing as mistakes can be costly in more ways than one.

For your neck sizing, I would suggest that you use a full length sizing die, but set it so that it short sizes. With a case fired in your rifle, set the die so that you can detect a slight buldge at the shoulder/neck juncture. You will be able to see this if you look very closely. Chamber that case and take notice of the resistance of the bolt on closing. Adjust as necessary. I prefer to feel an ever so slight resistance. This will ensure that you are headspacing on the shoulder. Your cases will last longer, and require less frequent trimming. Every rifle is an idividual, it just takes a little experimenting to find the "sweet spot". In regard to a DGR, full length sizing may be a better option for absolute reliability.

Best of luck with your new passion! George

To try and answer your question, fitting the cartridge to your firearm is the name of the game! Due to differences in each individual firearm (garenteed by the manufacturing process) applying measurements directly from a manual is not going to work very well.

Headspace ranges are established by industry advisory bodies, government bodies, or by individual manufacturers. In the U.S. the primary advisory body is the Small Arms and Ammunition Manufacturers Institute (SAAMI). Issues surrounding the ability to easily produce, safe mechanism reliability with a particular cartridge must be considered. Firearm manufacturers must turn out firearms with chamber headspace that is producible within a certain range of measurement, yet assures safe and reliable operation with all ammunition made within a certain standard. This becomes an extremely difficult challenge when designing self-loading firearms. It is also very important for us to understand that an ammunition manufacturer’s product must always be made at least slightly smaller than the minimum SAMMI chamber dimension to ensure chambering in all firearms of that caliber.

First of all, shooters are sometimes somewhat benignly confused by references to “headspace”, when in fact the more precise term that should be used is “chamber clearance”. The problem is exacerbated because many people freely interchange the two terms. When we refer to “case headspace” measurement as “a shortening of the case measurement”, it is actually a "decrease" in chamber clearance. A “headspace” measurement does not appear on any cartridge specification drawing; rather it only appears on chamber specifications! The actual true "headspace" measurement which is the distance from the bolt face to a datum line on the chamber shoulder (in a rimless cartridge) does not change. The headspace measurement is thought to "increase" because there has been an increase in the difference between the chamber headspace measurement and the now shortened case “headspace” (in this instance “length”) measurement. This increase is caused by the measurement of a shortened case body, caused by the shoulder having been set back, which is reflected as a "decrease" in case headspace measurement.

True “headspace” is determined by measuring the interior dimensions within the chamber of the firearm by making a chamber cast or by the use of special headspace gauges. The resulting measurements are then compared to SAAMI chamber specifications to see whether that particular chamber remains within the minimum/maximum measurements set out by SAAMI, or if there is indeed a “headspace” problem.

In a very general sense, headspace is the size of the cartridge chamber designed to accept a particular cartridge. The key to defining headspace is by determining minimum and maximum dimensions from the locked breech to either a contact surface or designated datum point in the rifle chamber, or to the rear of the barrel. The points of measurement chosen depend on the type of cartridge case used, rimmed, rimless, semi-rimmed, or belted.

I hope this is of some help to you. It really is just a longwinded way of saying each firearm is going to be different so you have to fit the cartridge to whatever you have! Have a great day.

"I have been troubled lately about this concept of correctly headsizing my casings. Not exactly sure how to get the correct amount of shoulder knock back.

I bought a hornady headspace gauge and have been doing some measuring of my shot casings and comparing them to new casings, but I am a little concerned about having the correct amount of headspace when I resize my casings."



Mark, the following is what I do for cross-the-course and long range highpower competition. X-course requires smooth feeding for rapid fire segments. This requires that you bump the shoulder back some. That said, I typically utilize the same sizing process for my slow fire long range rounds (1000 yds) with excellent results.

Step 1. Measure 5-10 fired cases of the same manufacture with your Hornady gauge. Average the measurements.

Step 2. Adjust the die in the press and resize cases until you are setting the shoulder back 2 or 3 /1000's from your average number. While adjusting and sizing, use a different case each time. This assures you don't over-work the neck of any one case.

Once the die is set, if you change brass, you will most likely need to repeat this process and reset the resizing die.

These steps will insure easy cartridge chambering. I can also say that bumping the case shoulder by this amount has never affected accuracy on any rifle I have owned.

Finally, I would like to mention that, bullet seating depth and proper neck tension can have a profound affect on accuracy after the optimal powder charge weight has been established.

Regards,

Before you get too confused; Headspace is
the clearence between the case head and the face of the bolt (or breech).
A chamber has no headspace of itself.
The dimensions tabulated as "headspace " are
datum measurements. It' the equivalent of
saying New York is 500 Miles from Cleveland,
yet both are located relative to Greenwich.
It is also true that more BS has been written
by "Gun Writers" about headspace than politics.
Take Care!

[quote]the Lee reloading manual has a headspace measurement for each caliber in its reference materials. Is this the number I should be using?"

Lee is unique in that. Interesting number but irrelivant to us, our chambers are what they are.

"Any thoughts or tips about getting the right headspace number????"

Yeah; forget it. The numbers on your gauge are only relitive, not absolutes, nor do they need to be.

Consider "headspace" as ONE thing - no matter what the specification is or what it's taken from, headspace is the space the cartridge fits into and that's ALL it means to a reloader.

Meaning, if a resized case won't fit the chamber, size it smaller. If the case is too small it will fit sloppy and streeetch excessively each time it's fired. Use your gauge to adjust your sizer and make your cases fit right.

First, gauge where the shoulders are after firing. Adjust your sizer in tiny increments until the shoulders are restored to that same point, there's no reason to go further back. After firing, cases have already shrunk back some from full chamber length so resizing further only increases case stretching more than neccessary.

Thanks for help all. I appreciate the posts.

Ammoloader - you referenced neck tension. One follow up there..

Is this referring to crimping? Should I be crimping my finished seated bullets? Is it correct to say that a non cannelured bullet should never be crimped?

quote:

Originally posted by Mark M.:
Thanks for help all. I appreciate the posts.

Ammoloader - you referenced neck tension. One follow up there..

Is this referring to crimping? Should I be crimping my finished seated bullets? Is it correct to say that a non cannelured bullet should never be crimped?

Mark

Generally, folks don't crimp bullets without a cannelure. That's when you start to talk about neck tension. To precisely control neck tension you purchase a sizing die with interchangeable neck bushings. You choose the bushing size based on measuring the OD of the cartridge neck with your bullet seated in the neck. Take that measurement and subtract 2 /1000's. This is the size bushing you start and in my experience, usually end with. There is one bushing manufacturer (Wilson I think) that makes one side of the bushing 1/1000 smaller. You can flip it over for a little more neck tension.

Redding makes a good full length sizer with interchangeable neck bushings. There may be others on the market now. There is also a fellow that will convert any die you send him to an interchangeable neck bushing for a reasonable price.

Also, I typically do not crimp bullets that have a cannelure if it is not required to control bullet position during operation of the bolt or recoil.

Have Fun!

The best thing I've ever found to make sure my cases were correctly sized is the case comparator, or what some would call a case gauge. It is a small cylindrical apparatus that has had a "chamber" machined into it exactly the size of a perfectly-sized case, plus about 0.001 RCH. If you size your case and the head is flush with the lower machined level (there are two) of the comparator of the end with the larger opening, your case is correctly sized and will go into your rifle perfectly. The smaller opening is used to indicate if your brass needs trimming. The end with the smaller opening also has two levels. If the inserted case is flush and/or up to the upper level, it is OK. Above the upper level means a trimming is in order. You get them from Sinclair. They are known as Wilson Case Gauges. Cost is $25 plus that $10 shipping charge. An easy way to avoid this expense is to turn your dies in 1/4-turn past contact with the shell holder when the ram is fully up and the die and shell holder are in contact. I learned this the hard way...

One more angle to this....

Suppose, for example, I have three different .223 rifles and I want to load some shells to shoot in any of my rifles.

Does the fact that a reloaded shell may be shot in any of my rifles change my approach at all??

Thanks to all again.

quote:

Does the fact that a reloaded shell may be shot in any of my rifles change my approach at all??

Yes, because every rifle is different. Every bullet is different, every case is different, every primer is different, every powder charge is different, every squeeze of the trigger is different and every condition under which the round is fired is different. This is for the benchrest guys who lose a match if they don't get ten rounds from 200 yards into an area the size of the fingernail on your smallest finger. But for general shooting and plinking, if a group of two inches from 100 yards is satisfactory, I wouldn't go into the tedious exercise of developing three loads for three different rifles in the same caliber...