The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Reloading How to determine COAL?Go | New | Find | Notify | Tools | Reply | |
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I'm new to reloading. After I've trimmed the case to the proper length and primer inserted and powder charge in it and I seat the bullet, how do I determine the proper overall length? The Speer manual gives lengths for various Speer bullets but the online data, such as that from Hodgdon, do not list the lengths. I just looked at the Nosler site (I will be loading some Nosler bullets) and they do not give a COAL. Is there some single place that will list the proper length? Oxon | ||
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Yeah, but Nosler has it right. The "proper" OAL is determined by the rifle and the load, not a book. All the book makers give us is the OAL they used for their rifle when putting the book loads together, their OAL is no more a law for us than their powder charges are. Perhaps the simplist way to get close to the MAXIMUM OAL is to split a sized case neck with a Dremel tool. Then start a bullet and chamber the case so the rifling can push the bullet back. Measure that OAL and get the max length for that bullet in that chamber. Then set your first test loads maybe 10, or more, thou deeper and develop the best powder charge for that bullet. Then, still using that best charge, do a series of seating tests by going deeper in maybe 5 thou steps until you find the best shooting OAL. Use an ogive type device to get the actual bullet jump to the lands, it doesn't matter where the points hang in mid-air! The "best" OAL should be a range of some several thou, not a specific point +/- nothing. Seat in the middle of the good shooting range and your accuracy won't be too quirky. Most factory sporters seem to shoot their best from maybe 20 thou to as much as 100 thou off the lands. From that you can see it really isn't critical to find the exact max OAL within a half gnats azz, all you really need is a fixed starting point to do your testing from. | |||
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Jim - thank you very much!! That's a very clear answer and I will do the "split-neck" maneuver. Makes a lot of sense. Thanks again! Oxon | |||
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Oxon What Jim c.<>< has said is true. But these aren't beginning reloading techniques. Although not all data manuals list a COL, the COL is a SAMMI defined length. If you look in several manuals those that have them all agree on Cartridge Overall Length. This is as much for magazine length as any thing. As too long a cartridge may prevent loads from being placed in the rifle's magazine. That said the COL gives a new reloader a definite length which will work in all cases in all rifles. muck | |||
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I find the dowel method easier. With the bolt of your rifle closed insert a wooden dowel down the muzzle and mark where the dowel enters the muzzle with masking tape. Now move the dowel back about 5 inches Now, take your bolt out and place a bullet into the chamber and force it into the lands with a pencil. Now gently insert the dowel until it touches the bullet that is pressed into the lands and mark where it stops at the muzzle with masking tape again. Measuring the distance between the two tape lines gives you max COAL to the lands. For hunting loads most people go 10/1000 off the lands for bullets other than Barnes. Barnes recommends 50/1000 off the lands for their bullets Now you need to check two more things. 1. Will it fit in the magazine? 2. Do you have at least 90% of caliber diameter seated in the neck of the case. Seat the bullet deeper to accommodate items 1 and 2 above. I find this easier than split neck because the split neck ends up having varying tension and if you do the split neck procedure 5 times, you will likely get 5 different measurements. Mike Never under estimate the internet community to use any opportunity to reply to a post with their personal rant about their tangentially related, single occurrence problem.  What I have learned on AR, since 2001: 1. The proper answer to: Where is the best place in town to get a steak dinner? is…You should go to Mel's Diner and get the fried chicken. 2. Big game animals can tell the difference between .015 of an inch in diameter, 15 grains of bullet weight, and 150 fps. 3. There is a difference in the performance of two identical projectiles launched at the same velocity if they came from different cartridges. 4. While a double rifle is the perfect DGR, every 375HH bolt gun needs to be modified to carry at least 5 down. 5. While a floor plate and detachable box magazine both use a mechanical latch, only the floor plate latch is reliable. Disregard the fact that every modern military rifle uses a detachable box magazine. 6. The Remington 700 is unreliable regardless of the fact it is the basis of the USMC M40 sniper rifle for 40+ years with no changes to the receiver or extractor and is the choice of more military and law enforcement sniper units than any other rifle. 7. PF actions are not suitable for a DGR and it is irrelevant that the M1, M14, M16, & AK47 which were designed for hunting men that can shoot back are all PF actions. 8. 95 deg F in Africa is different than 95 deg F in TX or CA and that is why you must worry about ammunition temperature in Africa (even though most safaris take place in winter) but not in TX or in CA. 9. The size of a ding in a gun's finish doesn't matter, what matters is whether it’s a safe ding or not. 10. 1 in a row is a trend, 2 in a row is statistically significant, and 3 in a row is an irrefutable fact. 11. Never buy a WSM or RCM cartridge for a safari rifle or your go to rifle in the USA because if they lose your ammo you can't find replacement ammo but don't worry 280 Rem, 338-06, 35 Whelen, and all Weatherby cartridges abound in Africa and back country stores. 12. A well hit animal can run 75 yds. in the open and suddenly drop with no initial blood trail, but the one I shot from 200 yds. away that ran 10 yds. and disappeared into a thicket and was not found was lost because the bullet penciled thru. I am 100% certain of this even though I have no physical evidence. 13. A 300 Win Mag is a 500 yard elk cartridge but a 308 Win is not a 300 yard elk cartridge even though the same bullet is travelling at the same velocity at those respective distances. | |||
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No. Because there is no one 'proper' COAL. Although they're 2 rules of thumb: 1. Seat the bullet so its base is at the shoulder/neck juncture. Or, 2. Seat the bullet the same depth as its caliber...for example, a .308 caliber bullet should be seated .308" into the case neck. Because the tip of some bullet types, exposed lead and hollow point, can vary quite a bit because of the manufacturing process, measuring COAL to the datum line on the bullet's ogive will give a more repeatable measurement. You'll need an attachment to your caliper to do so. Hornady makes the most widely used bullet comparator. | |||
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In a couple of rifles I regularly seat bullets to 50% of bullet diameter and have no problems. In harder kicking calibers I usually seat to listed OAL and then crimp. With a Lee Factory Crimp die you could probably seat out even further if your rifle will allow it. Just keep the bullet off the lands of the riflings. "The right to bear arms" insures your right to freedom, free speech, religion, your choice of doctors, etc. ....etc. ....etc.... -----------------------------------one trillion seconds = 31,709 years------------------- | |||
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Thank you - this is all very helpful. I think I understand what goes into COAL a lot better now. I'm reloading .300 Win Mag for a bolt action and 9.3x74R for a double rifle. I loaded a few .300 last night and after the propane guy gets done here this morning I'll try them out on the range! Thanks again. Oxon | |||
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