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reloading .243

20K views 10 replies 10 participants last post by  BKeith 
#1 ·
I am new to reloading, was trying to find out what the exact bullet deph is suppose to be , , i am reloading .243, hornady 58 gr v-max bullets, this is what i found , is this the best way or does anybody else have any suggestions, Thanks Bullet Seating Depth
Bullet seating depth has a great impact on rifle accuracy. The bullet seating depth for each individual rifle and bullet varies and should be set accorgingly.

NOTE: Do not use this procedure for rifles chambered for weatherby cartridges as these have long throats cut into the rifles bore.

Step 1. Insert a bullet into the neck of a unprimed resized case. Do not fully seat the bullet but seat it deep enough that it is gripped fully by the cartridge neck.

Step 2. Using a black magic marker or dykem steel layout blue, color the entire bullet.

Step 3. Insert the case and bullet into the chamber of the firearm and gently start to close the action. Stop as soon as you feel resistance.

Step 4. Remove the cartridge from the chamber, now look at the bullet, it should have well defined marks where the bullet contacted the rifling in the barrel.

Step 5. Continue seating the bullet deeper and chambering the cartridge until you only feel a slight amount of resistance when the bolt is closed completely. There should only be marks left on the bullet from the lands of the barrel.

Step 6. Now take another resized casing and with your bullet seating die set, repeat seating another bullet in the cartridge case to verify that this is your maximum cartridge length.

(NOTE) Never start working up a load with a bullet set against the lands in the barrel as this will sky rocket your load pressures.

Step 7. Shorten your cartridge maximum length by .06250" or 1/16" this is where you want to start to tune your load for seating depth.

(NOTE) Best overall accuracy, velocity, pressure uniformity and overall bullet performance will usually be obtained with most bullets seated from the barrels lands between .062" - .005".

Checking Accuracy
Once you have loaded a round of ammunition for your rifle there is one final step that you can take that helps eliminate fliers before you go to the rifle range and that is checking bullet run-out.

Bullet Run
 
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#2 ·
Those are good instructions, but often magazine length will be more of a factor in determining bullet seating depth than being able to get a bullet a few thousands of an inch off the lands.

The basic rule of bullet seating is seat bullets one caliber deep. With that said most factory rifles have the throat cut for the longest bullets fired in a specific caliber. In the 243's case that means for at least 105 grain bullets. If you shoot lighter (usually this means shorter) bullets then getting them out to within a few thousands of the rifling means seating depths that sometimes won't hold a bullet stable enough to feed from a magazine.

You can alleviate this to some extent by loading these singly instead of loading them from a magazine, but that makes your rifle a single shot. Most rifles will tolerate the bullet jump from case to rifling and still give good accuracy. I shoot 55 grain Nosler ballistic tips in both my 243's and they give good accuracy and they jump a ways to the rifling.
 
#3 ·
Yes, you can do as you stated in your post. The advantage of the exercise you described is it will let you do your seating relative to the ogive profile on the specific bullet you are loading as compared to a less accurate method of OAL from the tip of the bullet. Since bullets have different ogive profiles you will be best served to do it for each different type of bullet you shoot.

Be aware that the OAL, regardless of what method you use to determine seating depth, will sometimes be governed by what will fit and cycle through the magazine.

I use a very similar method to determine seating depth myself. Most of my guns get the best accuracy when I'm within .010" of the lands. There was a good article in one of the gun rags recently where the author claimed .030" off the lands is where he usually ends up and his article verified that .025" off the lands were his most accurate loads.

Good luck.
 
#4 · (Edited)
Fullthrottle275, you may wish to consider the following in relation to reloading relatively short length bullets :

Notes on setting up a ‘dummy’ case for bullet seating purposes :
1. Use a fine hack saw to cut two case neck slits down to the shoulder - remember to remove any burrs. The slits reduce the frictional force on the bullet, allowing it to easily slide into and out of the neck. There is also less chance of the bullet being tightly jammed in the lands when the case is fully inserted into the chamber.
2. Drill the case’s primer hole out to about 3mm.
3. Shape a small hook at one end of a thin, stiff piece of wire – to be inserted into the enlarged primer hole (hooking onto the internal lip of the primer hole) and gently pulled to extract the cartridge from the chamber - rather than using a rifle’s more forceful ejection system which will possibly change the bullet’s precise position resting against the lands.

Warning : I seat SHORT length bullets (eg. 6mm Hornady 65 Gr V-Max) deeper off the lands due to the fact that their boat tail design noticeably reduces their contact bearing surface in the case’s neck. I allow a minimum 3mm of neck surface contact and generally handle such ‘short bullet’ cartridges with more care as the bullet can easily be knocked out of alignment with the bore.
Where relevant, a cartridge’s maximum OAL will also be determined by its clearance in the magazine – thankfully not an issue with my old Browning B78 High Wall single shot falling block lever action rifle.

Method used for seating a bullet off the lands :

1. Partially insert a bullet into the slit neck of a properly sized, fireformed unprimed ‘dummy’ case.
2. Insert the cartridge into the chamber and exert light pressure with a finger against the base of the case so that the bullet’s tapered nose or ogive makes contact with the barrel rifling grooves or lands.
3. Then, fully insert the case into the chamber.
4. Carefully extract the cartridge from the chamber – use wire hook in primer hole.
5. Measure the OAL or length of the cartridge - from the bullet’s tip to the base of the case.
6. Repeat Steps 1 to 5 a number of times and then calculate the AVERAGE OAL.
7. Note : This AVERAGE measurement should be the maximum cartridge length for that bullet in that rifle, with the bullet’s ogive just touching the lands of the barrel.
8. Subject to magazine clearance, seat the bullet in a properly sized, fireformed primed case to a depth that results in a cartridge with an overall length 0.3 mm shorter than the maximum cartridge length – resulting in the bullet’s ogive being 0.3 mm short of the lands.
9. Test fire several cartridges – check the PRIMER pressure levels etc and overall grouping size – further reduce the cartridge’s overall length if required.
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#6 ·
Wow, good instructions, been doing it that way myself for years. Reality: most of the time, the suggested OAL for any bullet, from a makers manual, is a very good place to start. I have loaded garden variety bullets from Speer, Sierra, Hornady, and Nosler, in several calibers/rifles over the last 40 years, and I do not recall any problems with specified OAL from any of them. If you're not getting the accuracy you think you should from a specification, try turning the depth out a half turn for a set, and in a half turn to see if there's a trend. But usually charge weight is a better place to look for improved performance.
 
#9 ·
Bill,

Go to any particular forum and click on the "new thread" button at the top and bottom left (immediately above and below all of the posts on the page on the left side).
 
#10 ·
I used magic markers and match smoke on bullets for years and finally broke down and bought a Honady OLA gage. It is easier and faster to use and much more accurate.

Barstool(er)
 
#11 · (Edited)
I guess I do it the hard way. I drill a hole in the base of a piece of once fired brass resized with .001 bump on shoulder,that a cleaning rod goes through and I open the neck so a bullet can be pushed in and out with some resistance.
I push the bullet fairly deep in the neck, drop the bullet into the chamber, tap the base with rod a couple of times to be sure it's all the way in. Insert the rod in the hole and push the bullet out until the lands stop it. Slide the rod down the barrel to push the bullet and case out, then measure it with the caliper and guage, log it into my log book for that bullet so I don't have to measure it again. Very quick, easy and accurate. Please note, measuring to bullet tip IS NOT a very accurate measurement and I don't recommend doing that.
One other thing, pushing a bullet into the lands and then pulling it back out with the brass can give you bad readings because they stick in the lands and can pull back out of the brass some when pulling the brass out.
Also is a pick of the guage I use to measure my chamber for max case length. The black piece is inserted into brass that neck is cut way back on and then chambered. The chamber neck will push the guage into the brass as you close the bolt, take it back out and then you measure the length with calipers.
Here are some pic's.
Now, with all that said, with many factory barrels it's all useless. As mentioned, the magagine is going to determine seat depth, unless you plan to shoot single shot, and you probably will never find brass long enough to reach the chamber length in most factory chambers, but there are exceptions, Like the Tikka's.

http://i903.photobucket.com/albums/ac239/BenKeith/Picture15_zps01c013ca.jpg
http://i903.photobucket.com/albums/ac239/BenKeith/Picture14_zps905fbc10.jpg
http://i903.photobucket.com/albums/ac239/BenKeith/Picture13_zpsb59a6d86.jpg

Also note: You can also use the seat dept guage as a very accurate bump guage. Just use an insert in a large enough caliber that it goes part way down on the shoulder of the case. Then set your FL die so it bumps the shoulder down .001" - .0015".

Since it's almost impossible to get a consistant bump by trying to adjust the die, and I don't want to pay the megga bucks Redding wants for their competition shell holders, I use copper or aluminum shim stock and cut a horse shoe piece the thickness I need and epoxy it to the top of a shell holder, close it up in the press snuggly against the die and let it cure over night. Clean it up and run a stone over it a couple of times the smooth it and you have a shell holder that will give you a perfect bump each time. To determine the thickness, resize a pieces of brass with a feeler guage between the die and shell holder. .008" is a very common thickness for me.

NOTE: I changed the first line, I forgot I have been using resized brass for several years, but was looking at my old notes when typed. The difference between new brass and resized brass can be as much as .010"
 
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