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So is it ok if you are below the limit just not as accurate as your round could be?
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1st time out loading my own 270 and 06
- Thread Starter FishnhuntOR
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Depending on the rifle and how it is set up and chambered. I usually set a chamber depth so that OAL puts the desired bullet weight and shape about 5 to 7 thousandths off the lands. some rifles like more, some less. You can play ( with in reason) with OAL once you KNOW where your lands start and this will usually find the sweet spot your rifle really runs at. Many times, the load that works best with a given bullet will be under the max spec OAL, all you can do is try it out and see what your rifle responds best to!
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Okaaaaaaaaaaaaay. At the risk of repeating a method that has been posted here before, lemme show you how to establish the INITIAL complete overall length of ANY individual rifle cartridge, for a cost that does not exceed that of a spare [and re-usable] bullet, and an empty case. The fairly costy device formerly known as the Stoney Point cartridge length gauge is not required, not anything like it.
1. Take a once-fired, or even new, cartridge case, and neck size it. The will make sure that any bullet that fits into it is a good tight fit.
2. Next, destroy that tight fit by cutting three slots vertically from the open case mouth down to where the shoulder begins, or slightly less.
3. You now have a cartridge case with a slot cut into the neck at 12, 4 and 8 o'clock as you look down on it. All with me so far?
4. Take one of the bullets that you intend to use as a reload, and insert it into the neck. It SHOULD just be held there - not tight - but not so's it will move without a little pressure. You should insert it just past the boat-tail, so that it really protrudes.
5. Carefully insert it onto the open breech of the rifle, and SLOWLY fully close the bolt. This will not only chamber the cartridge, but will push the bullet up against the rifling in the part of the breech known as the 'leade', and, because the bullet is only gently held by the fingers you have cut in the neck, it will not engage the rifling at all.
6. Carefully and slowly open the action and remove the cartridge/bullet without disturbing the position of the bullet in the neck.
7. Measure it using a caliper - this is the maximum length of that cartridge, in THAT gun, with THAT bullet.
You can reduce that length from there on, until you hit the 'sweet spot' with your particular load, starting with, for example 5 thou less. [You HAVE got a a precision dial caliper, haven't you?]
Why was I being so insistent about THAT particular bullet? Well, each and every bullet manufacturer has a range of bullets that include spiffy names like Scenar, VLD [Very Low Drag] and so on. That refers to the ogive - the curve-shape of the bullet in the transition from a cylinder to pointy bit. A VLD bullet will have a very long ogive - to streamline it in the air and extend the range, but a hunting bullet will usually have a short ogive - a more beefy hitter from being slightly stumpier.
Both my .308Win rifles like the same amount of 'jump' to the lands of rifling - 15 thou, but both my 7mm like 20 thou, simply because the .308Win bullets I shoot are of the VLD style, and the 7mm are not.
It's simply a matter of trial and error, bearing in mind that any gap will somewhat reduce the initial pressure required to get the bullet started into the rifling - that little 'jump' just makes it a little bit easier.
Please use the money you have saved by not having to buy a $50 gizmo in the next 'Wounded Warrior' collection box you see.
Thank you.
tac
1. Take a once-fired, or even new, cartridge case, and neck size it. The will make sure that any bullet that fits into it is a good tight fit.
2. Next, destroy that tight fit by cutting three slots vertically from the open case mouth down to where the shoulder begins, or slightly less.
3. You now have a cartridge case with a slot cut into the neck at 12, 4 and 8 o'clock as you look down on it. All with me so far?
4. Take one of the bullets that you intend to use as a reload, and insert it into the neck. It SHOULD just be held there - not tight - but not so's it will move without a little pressure. You should insert it just past the boat-tail, so that it really protrudes.
5. Carefully insert it onto the open breech of the rifle, and SLOWLY fully close the bolt. This will not only chamber the cartridge, but will push the bullet up against the rifling in the part of the breech known as the 'leade', and, because the bullet is only gently held by the fingers you have cut in the neck, it will not engage the rifling at all.
6. Carefully and slowly open the action and remove the cartridge/bullet without disturbing the position of the bullet in the neck.
7. Measure it using a caliper - this is the maximum length of that cartridge, in THAT gun, with THAT bullet.
You can reduce that length from there on, until you hit the 'sweet spot' with your particular load, starting with, for example 5 thou less. [You HAVE got a a precision dial caliper, haven't you?]
Why was I being so insistent about THAT particular bullet? Well, each and every bullet manufacturer has a range of bullets that include spiffy names like Scenar, VLD [Very Low Drag] and so on. That refers to the ogive - the curve-shape of the bullet in the transition from a cylinder to pointy bit. A VLD bullet will have a very long ogive - to streamline it in the air and extend the range, but a hunting bullet will usually have a short ogive - a more beefy hitter from being slightly stumpier.
Both my .308Win rifles like the same amount of 'jump' to the lands of rifling - 15 thou, but both my 7mm like 20 thou, simply because the .308Win bullets I shoot are of the VLD style, and the 7mm are not.
It's simply a matter of trial and error, bearing in mind that any gap will somewhat reduce the initial pressure required to get the bullet started into the rifling - that little 'jump' just makes it a little bit easier.
Please use the money you have saved by not having to buy a $50 gizmo in the next 'Wounded Warrior' collection box you see.
Thank you.
tac
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This applies to normal cup and core bullets. If using a monolithic solid which is a harder bullet, it's usually recommended to have them at least .020" off of the lands to keep pressure spikes down.
@tac I'd never heard about splitting the case neck. Neat idea.
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If the magazine is long enough Tac's method works just fine to find the lands with a given bullet. I like to use a black sharpie on the projectile just so I can see the marks from where the lands start on the ogive when it makes contact with the rifling.
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I smoke 'em with a candle.
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Is that legal in this state?
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It is if you don't inhale 
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The soot from the candle will coat the bullet and then show the lands on the bullet It's actually an old smithing trick used to mark things before machinist marking dye!
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The candle smoke method is even cheaper than my method, and doesn't harm an innocent young cartridge case, either. However, remember that the bullet MUST be capable of moving within the neck - it must not simply jam into the lands.
tac
tac
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I've used the smoke/soot method for years. Just personal, but I like it better than the machinist blue for stuff like this. However, next time I need to I will try @tac's case trick. I wouldn't mind giving up a case for the cause and it's not like it couldn't be reused for the same purpose in different builds.
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