Have always loaded 308's and have always crimped Remington bullets in the cannelure. Now I want to load some 223's for my AR's. I will be using a bullet without a cannelure. Is .010 thousands too much neck tension for the 223? Just want to make sure I have sufficient tension when it slams into battery.
Neck tension question
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243winxb
Member
.003"
Blue68f100
Member
You will need to FL size for the AR. All FL 223rem die sets I know of have a expander on the depriming stem to expand the neck to proper size. This should give you around the 0.003" as stated by 243winxb.
243winxb
Member
Neck tension
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True, it gives around 35 to 45 lbs bullet pull. Seating the bullet should expand the necks a minimum of .002" But if using a bushing, brass spring back is outward, thats why i said .003" I have tested 223 brass. The 30-06 Not my test >
True, it gives around 35 to 45 lbs bullet pull. Seating the bullet should expand the necks a minimum of .002" But if using a bushing, brass spring back is outward, thats why i said .003" I have tested 223 brass. The 30-06 Not my test >[/URL][/IMG]
How does one measure the PSI of seating or pulling a bullet??
Reloadron
Contributing Member
I really don't think one can, not easily anyway. I gave it some thought once using a force gauge but a jig or fixture would need to be fabricated. Before I retired I had a nice machine shop at my disposal and while I don't miss work I sure miss that machine shop.
So yeah, with the right gauging it can be done but you would need to fabricate the fixturing or jig.Ron
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243winxb
Member
PSI, no idea, not mine. Its good for a comparison. I went by pounds, using a bath room scale, while pushing the bullets into the case. Military uses pounds, as does Federal.
i think .010 is too much. maybe with a really good chamfer on the case mouth and a boat tail bullet, it wouldn't be the end of the world. probably not going to give you super consistent velocities, if that's something you're worried about
Oh, OK. That sounds good. Just wondering. glad I didn't need to buy some new Sinclair expensive tool!
I am looking for the Angels on a Pin tool.
stubbicatt
Member
There are presses out there with PSI gages on them for seating bullets. Here's one I know of.
243winxb
Member
I don't think the force needed to seat a bullet is important for any ballistic issue. Instead, its the force needed to push the bullet out of the case neck. That's the industry standard and it's measured in pounds. Some military rifle ammo has a minimum spec of 60 pounds. Nobody uses the force to seat bullets as a spec for commercial or arsenal ammo I know of. M72, M118 and M852 30 caliber match ammo's case mouth diameters were about .3095" for the .3086" diameter 172-gr. FMJBT match bullet; it's release force was at least 40 pounds. A warm asphaltum sealer was put in the neck then the bullet was seated easily then the asphaltum cooled own and hardened "gluing" the bullet in the case mouth. Ball ammo with slightly smaller bullet diameters was made the same way except the bullets were crimped in place after seating them.
I've measured the force needed to pull a bullet from a case after measuring the force needed to seat it. It takes more force to seat them than push them back out. Especially if the cae mouth's been deburred the traditional way and its sharp edge scrapes the bullet as it's being seated.
Lets take a 7.62 NATO round that has a bullet release force spec of 60 pounds. To calculate the pressure needed to push it out,
1. calculate the cross sectional area of the bullet. For a .308" diameter one, it's .308 X .308 X .7854 = .0745 sq. in.
2. get the reciprocal of the area; 1/.0745 = 13.422. The area is a little over 1/13th square inch. For every pound of pressure per square inch, the pressure on the bullet will be about 1/13th pound.
3. to put 60 pounds of force on the base of the bullet, the pressure in psi has to be 13.422 times higher or 60 X 13.422 = 805 psi. A 4000 pound car with 30 psi in each tire whose tire footprint total for all four of them totalling 133 square inches (33.3 square inches per tire average) is how it's supported without flattening all the tires.
4. clamp a shell holder in a vise, put a case in it with a seated bullet, get a hook scale fastened to a bullet puller, put the puller on the bullet then pull it out. Firm constant pull is good enough. Read the scale when the bullet clears the case and it swings back to zero.
I've measured the force needed to pull a bullet from a case after measuring the force needed to seat it. It takes more force to seat them than push them back out. Especially if the cae mouth's been deburred the traditional way and its sharp edge scrapes the bullet as it's being seated.
Lets take a 7.62 NATO round that has a bullet release force spec of 60 pounds. To calculate the pressure needed to push it out,
1. calculate the cross sectional area of the bullet. For a .308" diameter one, it's .308 X .308 X .7854 = .0745 sq. in.
2. get the reciprocal of the area; 1/.0745 = 13.422. The area is a little over 1/13th square inch. For every pound of pressure per square inch, the pressure on the bullet will be about 1/13th pound.
3. to put 60 pounds of force on the base of the bullet, the pressure in psi has to be 13.422 times higher or 60 X 13.422 = 805 psi. A 4000 pound car with 30 psi in each tire whose tire footprint total for all four of them totalling 133 square inches (33.3 square inches per tire average) is how it's supported without flattening all the tires.
4. clamp a shell holder in a vise, put a case in it with a seated bullet, get a hook scale fastened to a bullet puller, put the puller on the bullet then pull it out. Firm constant pull is good enough. Read the scale when the bullet clears the case and it swings back to zero.
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spitballer
Member
I've never gone over .002", at least not on purpose. My manual advises that using the projectile to size the neck isn't such a good idea.
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