11 July 2002, 10:39
Hot Corequote:Hey snowcat, First off, let me say Moly Coated bullets can achieve higer Velocities at the same "Pressure" as Non-Coated bullets. But, to pick an arbitrary Velocity out of the air and attempt to get there is very dangerous.
Originally posted by snowcat:
So still trying to get 2800 out of 180's from my "06 AI and 22" tube. ...I am WELL over listed max loads and still seeing no scary pressure signs and velocities are in the low 27's. A few questions...
1) Having loaded only Ballistic tips and X's so far, how does one standardize seating depth with the generally deformed tips of the Partition bullets? You get your chamber length off the ogive but then seat off the unpredictable tip.
2) Moly. These bullets are moly coated. This apparently drastically affects pressures but is there some rule of thumb for load development? WQhat is this stuff doing to my bore? Cleaning? I did search past posts with out finding clear answers.
3) What's the standard velocity reduction per inch of barrell removed? I'm trying to evaluate my loads compared to factory. This gun is consistantly off by up to 150 fps. I have others that meet or exceed listed velocities even with shorter tubes than those used for the test data.
As always, thanks to all for taking the time to further enable my developing addiction.
Let me suggest you load to a SAFE MAX(aka watching the Pressure Indicators and ignoring the Velocity). Then just accept whatever Velocity you happen to end up with. If you want more Velocity, get a larger case or a longer barrel.
Overloading is a serious error. It creates "Metal Fatigue" in the Bolt/Receiver that simply can not be detected without special test equipment and chemicals. It shortens case life. And it indicates to everyone that you just do not understand how potentially dangerous an overload actually is.
Your #1. 1a) Pick any bullet out of a box and determine the Overall Cartridge Length(OCL) for that specific "Set-Up Bullet" to just Kiss-the-Lands. Use any method you are comfortable with. I use the old Flat Tip Jag in a Cleaning Rod Method.
1b) Put an empty case in the Press Shellholder and raise the Ram.(I trim all my cases, so they are exactly alike from shot to shot.) Screw your Seating Die into the Press until it touches the Casemouth. Back off the Seating Die a turn or so and secure the Lock Ring/Nut around the Sizing Die body with the Jam Set-Screw.
1c) Put the Set-Up Bullet in the Casemouth and ease the Seating Stem in until the OCL is the same as you originally measured in the firearm.
NOTE: Here is where the trick comes in.
1d) Return the case with the Set-Up Bullet at the correct OCL to the Shellholder and raise the Ram. Tighten the Seating Stem Jam Nut.
1e)Remove the Seating Die from the Press and with a 0.001" capable Caliper, measure the Overall(Seating) Die Length(ODL) and write that on the Bullet Box.
For example lets say your OCL was 2.775" and your ODL ended up being 3.875". Now if you want the Bullets from that specific box Seated 0.025" Off-the-Lands, you set the Seating Die to 3.850" ODL, screw it in the Press and begin Seating Bullets.
No need for any special tools and it is very accurate.
NOTE: It is VERY IMPORTANT to re-do this each time you open a new box of Bullets.
Due to Throat Errosion and Manufacturing tolerances, the ODL will vary slightly from box to box.
One last thing on this. Lets say you do this on a box of Bullets(we will pick 165gr Partitions), determine what the ODL is and shoot a few. Then lets say you practice over the Summer with 165gr Rem PSPs(to hold the cost down) and you run 300 bullets through the rifle. Then, re-do the ODL on the Partitions as if they were a new box to compensate for Throat Errosion.
2a) Moly is great stuff. I use it in every centerfire rifle I have. ALWAYS clean the rifle after you shoot it and leave a light coat of either oil or grease in the Bore. Just clean it as you normally would with one of the newer outstanding Bore Cleaners available today. Then grease a patch and run it through a couple of times. Finish with a clean patch to remove any excess lube.
2b)"Rob1SG" is correct that Bores can rust(and end up pitting) with Moly in them. Same is true for any Bore that has been shot and not cleaned/greased whether or not Moly is used. So, always clean/grease as soon as you get home after shooting, or just don't shoot the firearm. (I even clean mine at the Range.)
3a) There are Rules of Thumb, but there are no hard and fast exact numbers for this. Most folks use 25-28fps for 30-06 class cartridges. I use 1% of the Velocity as shown for a specific Load as shown in a good Component Manufacturers Manual for each inch.
Just "remember-to-forget" about the Velocity until you reach your SAFE MAX as indicated by your various Pressure Indicators and accept whatever Velocity it happens to be. Even 200fps doesn't amount to a pile of Impeached-Clinton on Game, but it could cause Metal Fatigue.
Best of luck to you.
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