Reloading - Looking After The Brass Cartridge Case By Matthew Cameron

Discussion in 'Technical Articles - Discussion' started by ADMIN, Dec 9, 2008.

  1. ADMIN

    ADMIN Administrator

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    This is a thread for discussion of the article, Reloading - Looking After The Brass Cartridge Case By Matthew Cameron. Here you can ask questions or make comments about the article.

    The author will have this thread automatically notify him of posts so that he can join the discussion. Here you can ask questions or make comments about the article.
     
  2. drhntr

    drhntr New Member

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    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
     

  3. Capt. D

    Capt. D Well-Known Member

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    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.
     
  4. Clinchriver

    Clinchriver Member

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    Nice informative article geared towards beginner target shooters.
    I always start with a full length resize, then trim and chamfer. Good Shooting
     
  5. Topshot

    Topshot Well-Known Member

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    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?
     
  6. drhntr

    drhntr New Member

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    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
     
  7. Roscoe

    Roscoe New Member

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    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
     
  8. RT2506

    RT2506 Well-Known Member

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    If you want to find out how far it is to the lands with a particular bullet here is a cheap way to do it.

    Take a unprimed case and full length size it and trim it to length. Now take a cutting tool like a hack saw or drimel and cut a line from the mouth of the case down to half way into the shoulder area. Before each use full length size or just squeeze the neck tighter with your fingers. Just start a bullet into the case with your fingers. Now slip it into the chamber and close the bolt. Open the bolt and ease the round out. The bullet should have been pushed back into the case when it hit the lands. This is the to the lands OAL. Measure the OAL and start seating the bullet however deeper, away from the lands you want to try. You can pull this bullet out of the case with your fingers when you get done and use it. You will need to do this with every bullt make and weight.
     
  9. Chuck Boyer

    Chuck Boyer Active Member

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    I know that the life of a case depends on how hard you push the round pressure wise and how many times you trim the case. You did not mention annealing. If you can, please enlighten your readers of the pros and cons of this procedure as it would be related to this topic. Thanks Chuck
     
  10. davewilson

    davewilson Well-Known Member

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    you can forget the sorting of the cases by weight or volume. it makes absolutly no difference.
     
  11. bryan c

    bryan c Member

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    I prefer using bushing dies for my resizing and like having total control over neck tension. However I dont have bushing dies in every caliber so one step I have added is to run the brass through the neck expander mandrel that you use to get the brass ready to turn the necks. I feel this lessens the amount of neck tension and makes it more uniform. I may be wrong but it seems to work well......great article
     
  12. kevin257

    kevin257 New Member

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    I have a "friend" who reloads for me. I gave him a 100 rnds of once fired brass to reload for me which i had marked for id purposes. the reloads i got back was not my brass and was beat to hell and back. upon questioning he responded that my brass was old and brittle so he replaced it w/ newer brass. Is this a crock or what? I have 100s of rnds of once fired brass, some from 30 yrs ago, so is age an issue? The specific rnds in question that were reloaded were Wby 257 at most 5 yrs old. the older brass i have is 270 win. Thanks.
     
  13. RT2506

    RT2506 Well-Known Member

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    You got ripped off. Real friends don't do this to one another. Those cases he ripped you off of run about $1.00 or so each now. I would confront him and ask him to prove that the cases were too brittle, which he will not be able to do because they were not too brittle if they were of the age you stated. I would ask to see those cases. I would be willing to bet that he will feed you a story about throwing them away or something like that. He most likely kept them for his own use or he sold them to someone else for the above mention $100.00 or so. With friends like that who needs enemies.
     
  14. bowhunthard

    bowhunthard Well-Known Member

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    Buy a Hornady Lock-N-Load O.A.L. Gauge, you won't regret it. This is by far the most accurate way to measure how far your bullet is from the rifling. If you really want to get serious about consistent measurements, get the Hornady Bullet Comparator also. Good luck.

    My 22-250 Savage 12LRPV likes a .0255" jump to the lands with 52gr Speer HPs, and my .308 700 VTR likes a 0.076" jump with 178gr A-MAXs. Haven't fiddled enough with my other guns yet, I just bought the O.A.L. Gauge about 2 months ago, along with the Comparator. Couldn't be more pleased.