COAL
Quote from Reloader on May 5, 2008, 7:50 pmI am very new to reloading, actually I just finished setting up my 550B and am confused on the COAL setting, the Speer manual I have gives a COAL of 1.135" for a 9mm 124g TMJ RN using 4.10g of TG the max listing in the front for 9mm is 1.169" MAX, the bullets I have are from Dillon and are of the bulk flavor but are 124g FMJ so where would I seat on the range? I read in the Speer manual that going below the min can cause excessive pressure.
And if I am using a Speer manual should I be using Speer bullets?
I am very new to reloading, actually I just finished setting up my 550B and am confused on the COAL setting, the Speer manual I have gives a COAL of 1.135" for a 9mm 124g TMJ RN using 4.10g of TG the max listing in the front for 9mm is 1.169" MAX, the bullets I have are from Dillon and are of the bulk flavor but are 124g FMJ so where would I seat on the range? I read in the Speer manual that going below the min can cause excessive pressure.
And if I am using a Speer manual should I be using Speer bullets?
Quote from Reloader on May 21, 2008, 5:51 pmThe pecs in the Speer manual are appicable to all bullets of that bullet weight, shape and description, regardless of manufacturer.
The pecs in the Speer manual are appicable to all bullets of that bullet weight, shape and description, regardless of manufacturer.
Quote from Reloader on August 16, 2008, 10:24 pmMr. 308 -
You are correct, the 9mm is very easy to "over load", so you should always follow manufacturer's reloading manuals. I would suggest owning several reloading books and having at least a double handful of the free booklets the power manufacturer's print. You can also print manufacturer's data off the internet.Here's were I believe you're getting confused. Lot's of lengths are being quoted for 9mm, from ~1.040" all the way up to 1.169" (the maximum length). If you consult one manual, it may say to load a certain bullet at 1.090", then you may see the same bullet in another manual quoting the 1.169" length. BUT, take great care to notice that the shorter COAL also has a REDUCED powder charge !!
If you think about this, the shorter cartridge must have a much smaller volume inside the case owing to the deeper bullet seating. Therefore, for any given bullet weight, a shorter COAL does not take as much powder to build the same pressure. This since the pressure is a mathematical function of the volume the powder is "working in". Follow?
So here's what we learn:
• Always use the COAL >>AND<< the powder charge from a single reference source. They are a "matched set" and must be used together.• When the COAL is reduced, the powder charge is also (usually) reduced. So pay attention.
• Just because a cartridge is tested to be pressure safe at a certain COAL does not mean the cartridge is going to feed nicely in YOUR pistol. Some pistols are very sensitive to cartridge lengths. If you have 2 different reference books with 2 different COALS, you might want to load a test batch of each. Longer is usually "gooder". (See #1 below.)
Other related concerns:
• Use common sense. Some hollow points, flat nose, and conical bullet shapes, where the nose of the bullet is flattened, cannot be loaded to 1.169". You have to imagine where the nose would have been if the bullet had a complete ogive. Then try to find a reloading manual for that weight bullet in that reduced length.• Some European manufacturer's guns (notably CZ) start their rifling much closer to the chamber than is customary in the USA. With SOME bullets this could mean that the bullet may need an even shorter COAL than the reloading manual calls for. BE SAFE. If you have a strange bullet shape, then load a test bullet into an empty case and drop it into your bare barrel. If the cartridge will not go all the way in AND spin freely, then you may have to shorten your COAL (and reduce your powder), or not use those bullets in YOUR pistol. This is very rare, but all the same you'll want to be aware.
As always. Record every load and COAL you use with each bullet type and brand in a notebook. In this way you'll be able to remember what works and what doesn't.
Hope this helps!
Mr. 308 -
You are correct, the 9mm is very easy to "over load", so you should always follow manufacturer's reloading manuals. I would suggest owning several reloading books and having at least a double handful of the free booklets the power manufacturer's print. You can also print manufacturer's data off the internet.
Here's were I believe you're getting confused. Lot's of lengths are being quoted for 9mm, from ~1.040" all the way up to 1.169" (the maximum length). If you consult one manual, it may say to load a certain bullet at 1.090", then you may see the same bullet in another manual quoting the 1.169" length. BUT, take great care to notice that the shorter COAL also has a REDUCED powder charge !!
If you think about this, the shorter cartridge must have a much smaller volume inside the case owing to the deeper bullet seating. Therefore, for any given bullet weight, a shorter COAL does not take as much powder to build the same pressure. This since the pressure is a mathematical function of the volume the powder is "working in". Follow?
So here's what we learn:
• Always use the COAL >>AND<< the powder charge from a single reference source. They are a "matched set" and must be used together.
• When the COAL is reduced, the powder charge is also (usually) reduced. So pay attention.
• Just because a cartridge is tested to be pressure safe at a certain COAL does not mean the cartridge is going to feed nicely in YOUR pistol. Some pistols are very sensitive to cartridge lengths. If you have 2 different reference books with 2 different COALS, you might want to load a test batch of each. Longer is usually "gooder". (See #1 below.)
Other related concerns:
• Use common sense. Some hollow points, flat nose, and conical bullet shapes, where the nose of the bullet is flattened, cannot be loaded to 1.169". You have to imagine where the nose would have been if the bullet had a complete ogive. Then try to find a reloading manual for that weight bullet in that reduced length.
• Some European manufacturer's guns (notably CZ) start their rifling much closer to the chamber than is customary in the USA. With SOME bullets this could mean that the bullet may need an even shorter COAL than the reloading manual calls for. BE SAFE. If you have a strange bullet shape, then load a test bullet into an empty case and drop it into your bare barrel. If the cartridge will not go all the way in AND spin freely, then you may have to shorten your COAL (and reduce your powder), or not use those bullets in YOUR pistol. This is very rare, but all the same you'll want to be aware.
As always. Record every load and COAL you use with each bullet type and brand in a notebook. In this way you'll be able to remember what works and what doesn't.
Hope this helps!