rapier5316
Member
Less than .002 runout, over 004 opens to .75 inch groups at 100 yards
Help me tighten my groups...
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Less than .002 runout, over 004 opens to .75 inch groups at 100 yards
rapier5316
Member
Those 2 groups were fired with rounds that were measured at less than .oo2 runout. When the runout of the rounds were .004 or greater the groups opened up to .75 inchs.
You are already shooting under MOA. Shrinking the 100 yard groups now becomes a matter of construction, developing shooting technique, ?
Most can eliminate the pesky flier by sorting their rounds and shooting scores with only the very straightest of bullet sets.
THis is also a fairly economic course of action. The RCBS case master can be had for under 90usd. Even the roller bearing Sinclair Int'l unit is under 100usd.
The rest of the equation here is: .22-284 using Lapua 6.5-284 brass sized to 224. Nosler 80 grain hp Match bullet. Federal large rifle magnum match primer using a 50 bmg powder. Firing in a 3 groove Lilja 1 in 8 twist with a finish length of 29 inchs plus the 1 9/16 inch brake.
You'll like the Leupold. Only 10 moa adjustment short of the Night Force for 4-500 usd less money.
You are already shooting under MOA. Shrinking the 100 yard groups now becomes a matter of construction, developing shooting technique, ?
Most can eliminate the pesky flier by sorting their rounds and shooting scores with only the very straightest of bullet sets.
THis is also a fairly economic course of action. The RCBS case master can be had for under 90usd. Even the roller bearing Sinclair Int'l unit is under 100usd.
The rest of the equation here is: .22-284 using Lapua 6.5-284 brass sized to 224. Nosler 80 grain hp Match bullet. Federal large rifle magnum match primer using a 50 bmg powder. Firing in a 3 groove Lilja 1 in 8 twist with a finish length of 29 inchs plus the 1 9/16 inch brake.
You'll like the Leupold. Only 10 moa adjustment short of the Night Force for 4-500 usd less money.
243winxb
Member
Why Brass Prep is Most Important.
A rifle chamber has a given volume, this runs from the bolt face to the place where the bullet seals the bore. Any time you change the weight/mass of the loaded round entering this volume, the pressures and velocity changes. The second most important is getting the loaded round centered with the bore. The best way to do (standard chamber, not tight neck)this is full length resizing using a bushing die,(Redding type S) while only sizing half of the neck area and controling the shoulder bump by pushing the shoulder back a mimimum of .002" The outside neck turning must be done to get the neck wall thickness exactly the same so it can center the round in the chamber. Neck sizing only in most cases does not work because 99% of the time the chamber is not in perfect alignment with the bore. Each time you fire the case it get larger in diameters, this changes pressures each time the case is fired, soon it will not chamber at all and will need full length resizing or as some call it, bump the shoulder back. Maybe if you put an index mark on each case and placed the case into the chamber the same as it exited the chamber each time this would not matter,maybe? 2 other ways to center the round in the chamber are 1. bullet jam, but as the gun gets dirty the jam changes. 2. Tight neck chambers used with custom dies. If you want to change your 3/4" average rifle into a 1/4" , case prep must be done IMO.http://findarticles.com/p/articles/mi_m0BQY/is_4_48/ai_83483904
A rifle chamber has a given volume, this runs from the bolt face to the place where the bullet seals the bore. Any time you change the weight/mass of the loaded round entering this volume, the pressures and velocity changes. The second most important is getting the loaded round centered with the bore. The best way to do (standard chamber, not tight neck)this is full length resizing using a bushing die,(Redding type S) while only sizing half of the neck area and controling the shoulder bump by pushing the shoulder back a mimimum of .002" The outside neck turning must be done to get the neck wall thickness exactly the same so it can center the round in the chamber. Neck sizing only in most cases does not work because 99% of the time the chamber is not in perfect alignment with the bore. Each time you fire the case it get larger in diameters, this changes pressures each time the case is fired, soon it will not chamber at all and will need full length resizing or as some call it, bump the shoulder back. Maybe if you put an index mark on each case and placed the case into the chamber the same as it exited the chamber each time this would not matter,maybe? 2 other ways to center the round in the chamber are 1. bullet jam, but as the gun gets dirty the jam changes. 2. Tight neck chambers used with custom dies. If you want to change your 3/4" average rifle into a 1/4" , case prep must be done IMO.http://findarticles.com/p/articles/mi_m0BQY/is_4_48/ai_83483904
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243winxb
Member
Your case prep. The sizing dies used and how the bullet is seated. Bench rest neck sizing dies run in a sleeve, this sleeve needs clearance to function, maybe it does not matter, but a bushing die that flrs at the same time keeps the brass held in a fixed position so the bushing can do its best work, much like a custom die.
243winxb
Member
http://www.redding-reloading.com/pages/typesbushseatdie.html Redding Full Length Resizing Die Type-S Bushing die.Can be use with or without an expander. With 1 bushing to start. An outside neck turner. A flash hole uniformer tool. Bullet seating i use a standard RCBS die, but a custom one might give better results. Your target will let you know if a different seating die is needed. I would hold off on the runout tool for now.
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I shoot 308 in a standard size chamber. I use Lapua brass and don’t turn the necks. I partially neck size with a Redding neck bushing die with the expander removed. I don’t size the body unless my brass becomes hard to chamber. I use a Redding seating die (the one with a micrometer). I get ¼ inch groups @ 100 yards. I don’t worry about runout since I can’t change it.
rapier5316
Member
Changing runout isn't really the point. Sorting the finished rounds by whatever degree of .oo you want is.
Bullet is using some good practices and is getting good results.
An interesting site is www.6mmbr.com
Bullet is using some good practices and is getting good results.
An interesting site is www.6mmbr.com
243winxb
Member
Any bushing die is far better than standard dies. NO EXPANDER, with or without neck turning. After measuring RCBS standard dies in 223,243, 30-06, i find that the neck is sized down .010" +. Way more than need. Then the expander ball opens the inside of the neck to the correct diameter. This overworking of the brass is where runout can happen. Problems with bushing dies and runout can happen also if the fired case neck(from a large chamber) has to be size down more that.008" to .010" http://www.redding-reloading.com/techlinepages/concentricity_bushdies.htm
243winxb
Member
Redding Teck Line & Tips
http://www.redding-reloading.com/techlinepages/techline.html Redding tips is saying outside neck turning will not improve Concentricity /accuracy with factory chambers> (oversided maybe
) I guess looking at your fired target is the only way to know. OOPS see update at the bottom, they were talking about standard dies, not bushing dies.
http://www.redding-reloading.com/techlinepages/techline.html Redding tips is saying outside neck turning will not improve Concentricity /accuracy with factory chambers> (oversided maybe
) I guess looking at your fired target is the only way to know. OOPS see update at the bottom, they were talking about standard dies, not bushing dies.
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243winxb
Member
Measure the neck diameter of 5 loaded rounds with a micrometer to get an average. The bushing i would buy would be .003" smaller then your average neck diameter. This should get your started with unturned necks. If you deside to outside neck turn, you may need a smaller bushing. You will end up buying at least 3 bushing.
The above was copied from here -
http://www.redding-reloading.com/techlinepages/bushingselection.htm
When I partially resize the necks of my cases I use 2 bushings to reduce the neck diameter in two smaller steps by using an intermediate diameter bushing. I’m not sure if this is necessary but looks like Redding recommends it. I have a tool that measures case concentricity. Haven’t used it for awhile. Think I’ll try Sorting the finished rounds by whatever degree of .oo you want. Like rapier5316 suggests sometime and see if I get any improvement. Some people weigh bullets and cases and sort by bearing length, point the meplats and trim the meplats. I’m not sure how much some of this matters. I would think it would take a very good rifle and shooter to see the differences. But as an old benchrest shooter once told me - you might not see a difference between one thing but when you add them up it makes a difference. I’m pretty happy with my loads but trying to improve groups can be fun.
rapier5316 -
What bullet speeds are you getting?
243winxb
Member
Bushings
http://www.redding-reloading.com/techlinepages/techline.html Titanium bushings need a light coating of lubricant to the case necks before sizing. A single shot rifle can use a bushing that is .001" smaller then the loaded rounds average case neck diameter when OUTSIDE NECK TURNING. A repeating rifle that will feed from a magazine may need a smaller bushing so you don't get bullet set back. Always check you bullet tension, if you can push the bullet into the case with you finger its to light. The expander is NOT used with neck turned brass. Brass that has NOT been NECK TURNED may need the expander used with flat based bullets if your sizing the neck as much as .003" A boatail bullet most times will Not need the expander. You have to make this determination by how much pressure/resistance you feel when seating the bullet. Aways use a nylon brush to clean the inside of the neck. No lube for turned brass. You MUST lube if using the expander. Use a Q-tip to wipe the lube out of the inside of the case neck after sizing.
http://www.redding-reloading.com/techlinepages/techline.html Titanium bushings need a light coating of lubricant to the case necks before sizing. A single shot rifle can use a bushing that is .001" smaller then the loaded rounds average case neck diameter when OUTSIDE NECK TURNING. A repeating rifle that will feed from a magazine may need a smaller bushing so you don't get bullet set back. Always check you bullet tension, if you can push the bullet into the case with you finger its to light. The expander is NOT used with neck turned brass. Brass that has NOT been NECK TURNED may need the expander used with flat based bullets if your sizing the neck as much as .003" A boatail bullet most times will Not need the expander. You have to make this determination by how much pressure/resistance you feel when seating the bullet. Aways use a nylon brush to clean the inside of the neck. No lube for turned brass. You MUST lube if using the expander. Use a Q-tip to wipe the lube out of the inside of the case neck after sizing.
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