chamber size, COAL

[Greybeard]

I'm planning on doing almost exactly that. Coming off the lands .005 and working down to published COAL. I wasn't sure what difference using the published minimum powder load would have when I was seating beyond the published coal. SO far I gather I should be fine. I'll be using a chrono and will check for pressure signs.

Your on the right track, but forget about going down to coal. The closer you are to your lands the more accurate you will be. Small increases/decreases of powder make a big difference.
Have fun.....

 

[Kman]

Your on the right track, but forget about going down to coal. The closer you are to your lands the more accurate you will be. Small increases/decreases of powder make a big difference.
Have fun.....

Sounds good. The next ladder will definitely be the powder. Thanks for the info and suggestions.

 

[Kman]

Most of the time the best accuracy is achieved loading with a longer COAL. I load mine right up to the rifling lands in my Ruger Rifles. The accuracy is best with the long COAL. In fact, I find my desired COAL for each type bullet by partially sizing the neck of an unloaded, clean case, inserting a bullet just a small amount into the case, and then seating the bullet by loading it into the gun and forcing the bolt closed. It should go in pretty easily, if not you have sized the neck too much, you want just enough neck tension to prevent the bullet from sticking in the barrel when you open the bolt. Then I take this unloaded parially seated bullet to the press, lower the handle, raise the cartridge, and twist the seating die down until it makes contact with the bullet at its current seating depth. Then, I lock the die in place, remove the unloaded cartridge, and turn the seating stem 1/8 further into the die.

It seems to work pretty well for me. You can then setup your ladder test by increasing the seating depth in small increments.

I also usually start with close to the max recommended load and work down, as the reduced pressure resulting from the increased space in the case will add to my safety margin.

I keep saying "I" because it works for me. Your results may vary.

There are sometimes that your COAL will be limited by your magazine space and/or by the bullet length.

Examples: Some guns have to be loaded as single shots to accommodate a long bullet, because they will not fit in the magazine. Some long skinny pointy type bullets will cause this.

Some bullets like a 55 grain in a 243 may be too short to load into the lands-there just is not enough bullet left to fit securely into the case neck when loaded too long.

Good Luck, check the facts, read some books, have fun, be safe, ect

You weren't kidding when you said your most accurate round is right off the lands!! My rem 700 was as good or better than the federal gold match I brought, started right off the lands .003. Unfortunately it makes it a single shot because it's so long. I need to finish the ladder and see what I get when I'm close to the book 2.80" coal. Man that was a great feeling shooting that 5 round string!!!!!

 

[1006]

If you are keeping the distance below 300 yards, you might like the round nose bullets. They will hit the lands sooner, producing a shorter COAL.

I have an FN Commercial Mauser in 7mm-08. I use 173 grain round nose bullets to get up to the lands and still fit into the mag.

I would load whatever bullet you like best and load them as a single shot at the range. If you hunt, you can use some shorter bullets.

 

[1006]

 

[Kman]

If you are keeping the distance below 300 yards, you might like the round nose bullets. They will hit the lands sooner, producing a shorter COAL.

I have an FN Commercial Mauser in 7mm-08. I use 173 grain round nose bullets to get up to the lands and still fit into the mag.

I would load whatever bullet you like best and load them as a single shot at the range. If you hunt, you can use some shorter bullets.

Thanks for the tip on the round nose!

 

[noylj]

KBs caused by low charge weights are for low charges of VERY slow powders in VERY large cases where the powder is divided between being right next to the flash hole and right next to the bullet and was found in lab tests to be impossible except under very rigid lab conditions not found while shooting, with the conclusion that such KBs in real life are almost certainly loading errors.
IF one wants to drop a start charge by a couple of grains, it isn't an issue. If one wants to drop the charge by more than that, move to a faster powder. It really is simple and has been done for over 100 years.
Now, for large bottleneck cases, the story goes that, unlike straight-wall pistol cases, that pressure can go UP as the bullet approaches the lede/rifling and can go down as the COL goes down as the case has a lot more space than a small pistol round. That is what the "experts" in the magazines say the factories have found in testing.
However, again, in the range that reloaders work within, establish your COL and work up the load from start. After that, if you want to move the COL, you will need to back off the charge a bit and re-work it up no matter which way you move the COL. Remember, in general, any talk about COL effects on pressure is with COL changes of over 0.100".
Personally, after over 40 years, all my rifles and pistols do best with the bullet as close to the lede as possible and loads are worked up from there.
The COL in a manual is the test COL and YOUR chamber is different and you may be using a different bullet that needs a different COL and your mix of components can produce the same pressure with a smaller or larger charge of powder. So, start at the start load.
For most rifles, the COL is the longest you use that fits the magazine (internal or external) and feeds and chambers. If you are loading single-shot, obviously all you need is that the rounds chamber.

 

[Kman]

KBs caused by low charge weights are for low charges of VERY slow powders in VERY large cases where the powder is divided between being right next to the flash hole and right next to the bullet and was found in lab tests to be impossible except under very rigid lab conditions not found while shooting, with the conclusion that such KBs in real life are almost certainly loading errors.
IF one wants to drop a start charge by a couple of grains, it isn't an issue. If one wants to drop the charge by more than that, move to a faster powder. It really is simple and has been done for over 100 years.
Now, for large bottleneck cases, the story goes that, unlike straight-wall pistol cases, that pressure can go UP as the bullet approaches the lede/rifling and can go down as the COL goes down as the case has a lot more space than a small pistol round. That is what the "experts" in the magazines say the factories have found in testing.
However, again, in the range that reloaders work within, establish your COL and work up the load from start. After that, if you want to move the COL, you will need to back off the charge a bit and re-work it up no matter which way you move the COL. Remember, in general, any talk about COL effects on pressure is with COL changes of over 0.100".
Personally, after over 40 years, all my rifles and pistols do best with the bullet as close to the lede as possible and loads are worked up from there.
The COL in a manual is the test COL and YOUR chamber is different and you may be using a different bullet that needs a different COL and your mix of components can produce the same pressure with a smaller or larger charge of powder. So, start at the start load.
For most rifles, the COL is the longest you use that fits the magazine (internal or external) and feeds and chambers. If you are loading single-shot, obviously all you need is that the rounds chamber.

I'm glad to see that what I've read is reiterated in your post. I've been cautious with the charge weight. The .308 is great because of all the available load data. Once I've had my fill of .308, I plan on moving to working up loads for my bolt .300 blackout. That's going to interesting with the endless range of combinations. I have ARs in .308 and .300 BO, but reloading is much more fun with the bolt guns right now!!

 

[Fisher7]

Start at the lands and work back .005 or .010 until you find the bullet node. Then start upping the powder charge until you find that node. Watch your cases for high pressure signs.
I will be doing this with my new 6.5x47L. After you get all that done then we can talk neck tension. You have just took the first bite of a small elephant. If you want to go down the rabbit hole ride with me one month to Swainsboro. 400 and 1000 yards. Aren't you just up the road from me?

 

[Kman]

1000 yards!! One day, but I'm just starting out. I can shoot in Madison and probably get a few hundred yards out there. If you can ever go during the week we could set something up. This is all new to me. I will say reloading has been on my mind often since I started back in April. It is a rabbit hole!!! We definitely don't live close to each other. I'm near 285 and 400.