Stupid question.

[DalesCarpentry]

I am pretty new to reading decimals. I just checked my 22-250 for the lands measurement. I used this method.
http://www.gboreloaded.com/forums//index.php/topic,112672.msg1098350243.html
Well my reading is 2.470 and someone here advised me to seat my bullet 10 thousands off the lands. Does that mean that I would have a COL length of 2.370 then? Thanks for your help Dale

[Graybeard]

Prolly but before you go worrying about being 0.010" off the rifling you need to first figure out what powder charge you'll use and then play around with seating depth.

I almost always start either at the bullet maker's recommended C.O.L. or with the base of bullet seated to the base of the neck. I use that and decide what powder charge seems to work best and only after I have locked in the powder charge will I mess with changing seated depth and quite honestly most times I find changing the seating depth isn't necessary at all.

Folks worry too much about how many thousandths of an inch they are from the rifling.

[DalesCarpentry]

Prolly but before you go worrying about being 0.010" off the rifling you need to first figure out what powder charge you'll use and then play around with seating depth.

I almost always start either at the bullet maker's recommended C.O.L. or with the base of bullet seated to the base of the neck. I use that and decide what powder charge seems to work best and only after I have locked in the powder charge will I mess with changing seated depth and quite honestly most times I find changing the seating depth isn't necessary at all.

Folks worry too much about how many thousandths of an inch they are from the rifling.

The recomended COL is 2.350 so I am really close to what is recomended. I am going to load 4 bullets each with H-380 starting at 38 grains 38.5, 39, 39.5, 40 and 40.5 grains and see witch one is the most accurate and shoots the tightest groups. I will check for pressure signs along the way. 41 grains is a max load and I really don't want to shoot max loads so I am hopping 38 or 38.5 grains shoot a tight group. Dale

[bobg]

   Not really a stupid question Dale. I seat mine deeper than that. If you want 10 thousands off the lands your dimensions are right. Still can't figure out why you use 50 grain bullets. I have always used 55 grain. If i wanted 50 grain i would go back to my 222. I will probably get a lot of flack on this but that is ok i am use to it.

[DalesCarpentry]

There is no real reason I chose the 50 grain bullets other than they are a little faster. I hope they shoot well out of my rifle. If they don't I will go to the 55 grain pills. Dale

[Tractorsaw1]

With the numbers listed he is loading 100 thousands off the lands.  .010 off the lands would be 2.460

[BruceP]

While every one is giving good advice as to how to work up a load I'll address the origional question for those who want to know not that you really have to know to work up good loads. The first digit after the decimal point is 1/10th the second  1/100th and the third 1/1000th.
So ten 1/1000th's would be equal to one 1/100th which as I said is the second digit. Graybeard typed it correctly in decimal form as 0.010".
So using your mesurement to the lands of 2.470" and going ten 1/1000ths shorter you would subtract one from the second digit behind the decimal point not from the first as you did in the origional post so the answer would be 2.460" not 2.370".

Like I said I know it's not really a must to know this to work up loads but it is the correct answer to the mesurement part of the question.

Bruce


While I was typing the long explaination Tractorsaw1 typed the short answer. 

[DalesCarpentry]

Thanks for clearing that up. Dale

[SHOOTALL]

2.470 - 2.37 = .1 or one tenth of an inch .
Try seating where the bullet touches the rifling then seat 1/4 turn deeper at a time until you find where your gun shoots best and will still feed . We could all suggest a COL. but each gun is different . The suggestion you got may be a good place to start in some guns though and I do not intend to cut that down. Just offer a different way with less math.

[OR-E-Gun Bill]

Trying to help you understand decimal measurements in your carpenter measuring world Dale:

1.000" = 1 inch      (1000 thousandths)

0.750" =  3/4 inch  (750 thousandths)

0.500" = 1/2 inch   (500 thousandths)         

0.250" = 1/4 inch   (250 thousandths)

0.125" = 1/8 inch   (125 thousandths)

0.010" = 1/100 inch   (10 thousandths) ---  or close to the thickness of 3 pages of the note pad you carry in your pocket.



As others have said, starting out handloading you'd be better off just sticking to the basics and then expand your horizons as you go. Have fun and be safe.
 
Bill

[jhalcott]

  Being a bit LAZY, I will mike a NEW factory load and seat the reloads to that length. Then after getting a good load worked up I MIGHT try a few different depths(cartridge overall length) to see if it helps.

[DalesCarpentry]

Yea I don't think I want to play around with the bullet seat depth as of yet. I am going to just make them like they say at 2.350 COL. Dale

[DANNY-L]

That's what I do and I'm happy with it. I also switched to the 50gr nosler b.t with 35.8gr imr 4064 cci 200 col 2.350 brass trimmed to specs,very impressive in my 700 ADL leaving practically one ragged hole @ 100yds.

[SHOOTALL]

I have found on some cases seating the bullet where the base of the bullet is flush with the bottom of the neck ( where it starts to be shoulder ) works great . But different bullet weights give different COL. as will bullet shape. Some set die with a factory round and I have done so but when doing so i find it best to crimp as a seperate operation .

[Graybeard]

Graybeard typed it correctly in decimal form as 0.010".

Yeah I kinda ignored his math and therefore I guess the real question asked and instead tried to give what I felt was better advice on working up a load than by worrying about how far off the rifling the bullet is seated. I don't even make that measurement anymore for my loads and just concentrate on what shoots accurately regardless of how far it is from the rifling.

[yooper77]

That is most definitely not a stupid question.  I always seat to bullet manufacturers recommended C.O.L. and concentrate on the best accurate powder loads, breathing and trigger pull.

I had a friend that was hooked on seating as close the lands as possible and during a hunting trip he ejected a loaded cartridge but the case was pull off the bullet that was stuck in the rifling and the powder fell into the magazine well.  He was left waiting until we got back to camp to get the bullet out, not a happy guy that day, but he learned something he will never forget.

I have never had a reason to mess with adjusting bullet manufacturers recommended C.O.L. in order to achieve the best accuracy in my rifle loads.

yooper77

[SHOOTALL]

why didn't he pull a bullet from another round and chamber the case and shoot the bullet out ? Most who seat that far out open the action in a way so they don't spill the powder if the bullet sticks. We live and learn.

[yooper77]

SHOOTALL,

You are so right live and learn.

I know what you mean, but this guy didn’t want to experiment in the field.  Back at camp he bumped the bullet out with a cleaning rod and told himself if he chambered another round he would fire it and not unload it.  He shot his deer during the trip and back at home he seated the rest of his loads to manufactures C.O.L.   Guess what, just as accurate too.


yooper77

[DalesCarpentry]

The recomended COL on my 22-250 is 2.350. Well after finding a good load I played around yesterday with the seating depth. I found by making the COL on them at 2.460" that I get groups under 1/2". It works for me. Take care Dale