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Reloading - Looking After The Brass Cartridge Case By Matthew Cameron

 
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Old 12-09-2008, 06:14 PM
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Reloading - Looking After The Brass Cartridge Case By Matthew Cameron

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Old 12-11-2008, 11:52 AM
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Re: Reloading - Looking After The Brass Cartridge Case By Matthew Cameron

I think your are 'On Target' so to speak. Your thread contains very useful information for someone wanting to get all they can from their firearm. Granted there are limitations to the capabilities of the weapon determined by manufacturing. I also believe that anything worth doing is worth doing right to an extent.

Your right, the person shooting a regular production rifle for mediun deer size game out to 300 or so yards can get by with some of the premium factory loads. I have friends that shoot them and have good success. If they are a new hand loader, they probably don't need to ream the primer pockets or outside necks. They will need to trim the cases to specified lengths, inside and outside chamfer the case mouths. There will also come a time after several firing when the inside of the case mouths will need to be reamed. Under pressure the brass wants to flow forward toward the mouth, the walls of the mouth thicken and get longer as you indicated.

I believe you also need to chamber the round for that particular rifle. Make sure the seating depths of the bullets are the same for each round. Every rifle has it's own amount of 'free bore'. So my 25-06 cartridges may/may not chamber in yours. The bullet may contact the 'lands' of the riflings. My Model 70 Win likes a .035" distance between the bullet and 'lands'. My 7mm Rem Mag likes .050" for best groups. I'm working on the 6mm x 284 load now, (I'm necking down Lapua 6.5mm x 284 brass for this one). Granted the 6 & 7mm are custom built rifles varmint/deer rifles with match barrels, Timney triggers, full floating barrels and glassed actions but they are not benchrest grade. The Model 70 is still factory, it does have a floated barrel but thats it. It shoots .075-.875" MOA (3 Shots) at 100 yds with my hand loads. The 7mm shoots a touch better.

I make sure the cases are all the same length, case mouths are inside reamed, inside/outside chamfered, weigh every powder charge and check the seat depth on every cartridge. I'm not at the 'trim' outside neck stage, but it is next nor do I weigh every new case and probably never will for these rifles. Another thig I do after fire forming the case to the chamber (Fire the cartridge for the firet time), I only "neck" size the brass afterwards during the reloading process because I'm only using the brass in this rifle and no need to use energy reforming a case everytime.

I'm not sure how accurate weighing cartridges is anyway to determine a difference in case volume? No one can't tell where the excess brass is located in the hull by weight? Your 'assuming' it's all in the case wall? A closer way is to use something like 'wax' to seal the primer pocket, fill the case with water then empty the water into your scales and weigh it for each cartridge. Now set yourself some comfortable number for % weight difference between cases. The difference in weight will directly correlate to the difference in volume. I do this when I'm looking for that rumored min (85% used case volume) for powder charges.

I have been reloading for 28 years and still learn new tricks/hints all the time. I enjoy threads like yours. Your never too old to learn. Reloading should be an opportunity to improve the accuracy and enjoy yourself, but safely. Don't let it be a means to an end, we tend to get sloppy/unsafe.

Don't let your ammunition be the limiting factor for the accuracy of your rifle. It's the cheapest correction, if done right.


Thanks again for the information




drhntr
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Old 12-11-2008, 10:41 PM
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Re: Reloading - Looking After The Brass Cartridge Case By Matthew Cameron

Very good read and a good place to start for folks like me that are just breaking into this game of long range precision shooting. Have narrowed my first build down to a 7 WSM or a 7 MM.

Understanding a little more about case prep which I understand, that was the crux of the article. However I read different things about run out, or being slightly off of, on, or slightly into the lands. The lands I assume in the start of the rifled portion of the barrel. How do you know that your bullet is touching the lands or not, where does this measurement come from and how is it obtained?

While this was an informative read to me, and I may be asking these questions in the wrong place, where might I find more information on precision reloading and that is hopefully simplified eough for a beginner to understand. I have a habit that when I decide that I am going to do something I tend to jump in head first. I recently received my NF glass for my build. Now all that I have to do is decide on a cal.
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Old 12-12-2008, 05:56 AM
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Re: Reloading - Looking After The Brass Cartridge Case By Matthew Cameron

Nice informative article geared towards beginner target shooters.
I always start with a full length resize, then trim and chamfer. Good Shooting
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Old 12-13-2008, 12:18 AM
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Re: Reloading - Looking After The Brass Cartridge Case By Matthew Cameron

Nice article Mathew,

You talk about the smaller calibres with regards to neck turning. I was wondering about the benefits with regards to the larger .338 size cartridges.

When making up a new custom rifle, Is it worth getting a tight chamber neck diameter cut into a .338 cal or would a standard size neck do?

If a tight neck is the go, what size would you recomend?
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Old 12-15-2008, 10:46 AM
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Re: Reloading - Looking After The Brass Cartridge Case By Matthew Cameron

Capt D.
The way I calculate how far off the 'lands' that I am is, I start with making myself a 'Dummy' round (Unprimed or resized fired case with spent primer still seated).

1) Make sure the case ia trimmed to length.

a) Resize the case.
b) Partially seat a new bullet in the case and try to chamber the round. You shouldn't be able chamber it at this time! The 'lands' should be stopping you from closing the bolt, don't force it.
c) Seat the bullet farther into the case and try again. I typically go about 1-turn of the seating screw at this point.
d) When I get close enough to where I'm at the point that the bolt will just want to break over, take yourself a 'black' magic marker and color the bullet.
e) Now go about 1/2 turn on the screw and rechamber. When you take it out you should see marks left by the riflings.
f) Continue this process until you don't see any rifling marks ( You have to re-color the bullet with each chambering attempt).
h) When I really close, I use 1/4 turns on the seating depth screw. When I don't see any marks, I seat the bullet to start at least 0.025" off the lands.

Now load about 5 rounds at 0.010" increments 'off' the lands a check your groups. Make sure you are off the 'lands' during this process. A bullet seated while still contacting the 'lands' will introduce a 'pressure' spike'. Some small caliber (22LR) rifles are done this way, but for calibers exibiting high pressures, I don't recommend it unless you back off of the powder charge.


For reading I have found a book titled "The Ultimate In Rifle Accuracy". I'm still reading it. The Author is Glenn Newick, ISBN0-88317-159-7. It covers just about everything you need from building your own rifle, bench techniques, readingwind and case preperatiom.

Maybe this helps?


Good shooting
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Old 12-17-2008, 07:19 PM
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Re: Reloading - Looking After The Brass Cartridge Case By Matthew Cameron

Quote:
Originally Posted by Topshot View Post
Nice article Mathew,

You talk about the smaller calibres with regards to neck turning. I was wondering about the benefits with regards to the larger .338 size cartridges.

When making up a new custom rifle, Is it worth getting a tight chamber neck diameter cut into a .338 cal or would a standard size neck do?

If a tight neck is the go, what size would you recomend?

I do not have any experience with larger calibres in relation to neck turning. I did read a US article recently that suggested that necks that are "cleaned up" about 80 per cent shoot better groups. I would suggest that this may be a better result rather than a fitted neck in larger calibres.

Shoot safely

Matthew Cameron
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