Reloading long C.O.A.L

[stevemiller]

How much would you increase in powder when working up a load that you are seating the bullet longer than sammi C.O.A.L.?I am working on accuracy with my rifles,Some are as much as .150 away from the lands.I realize that as I load longer I am increasing the volume of the casing,and lowering cup pressure and losing velocity.I would like to get back the lost velocity.Is there a formula that a re loader could look at to know how much pressure would be there to start,So they new that the bullet would in fact come out of the barrel?

Example:180 grain Nosler ballistic tip,IMR 4350 powder 70.grains. .300 Weatherby 26 in. barrel. Sammi seating depth is 3.533 or so,Im wanting to load out to 3.700 leaving .012 to the lands.

[bobcat]

I don't think the seating depth makes that much difference in pressure/velocity. I wouldn't adjust the powder charge at all. But if you want more velocity go ahead and increase the powder until you get pressure signs. The best tool to have is a chronograph if you want the maximum velocity possible out of that cartridge. I normally just load to the max charge in my book. But with a chronograph you would know how much you're losing with the longer seating depth. I doubt it's very much, probably less than 25 fps.

[b23]

Keep in mind, when you start getting close to the lands, the closer you get the faster the pressure curve spikes up so you can have a load that doesn't show pressure when it's loaded 30 thou off but has heavy bolt lift or ejector marks when it's 0-10 thou off.  Pressure starts ramping up pretty quickly when you get within 10 thou and less.  Just something to keep in mind.

[BULLBLASTER]

Seating depth absolutely has a pretty good impact on pressure and velocity. It does decrease as you go longer until you get right up to the lands if you are very close or touching the lands it can cause pressure to spike.
It is always important to be very careful when deviating from published load data. And a chronograph and ability to identify pressure signs is very important.
Also be careful if you are right on the edge pressure wise because changes in weather can put you over pressure very quickly including moisture in the chamber.

[BNAElkhntr]

No Need to increase COAL in a Weatherby   they are free bore     This technique works best in other guns

[MuleySniper]

I was loading for my .257 wby for the first time last night. I was trying to determine the lands on my 700. I gently seated a bullet shallow into a new formed brass and carefully chambered it into the rifle. I felt zero resistance from what at least I could feel. Measured the COL and was around .25 longer than the max COL in my speer book. I tool black marker and covered the bullet and re chambered not noticing any markings.  The books call for 3.24 and some 3.25 and I was 3.5 something. I looked online and saw some custom non book loads guys had that were measuring that long. Im still unsure if I touched the lands or not but it made me a little concerned. I haven't charged any rounds yet because I am still a little confused on how long I can get away with and still be safe.

[b23]

Loading manuals COAL is mostly based off what they know will cycle through the magazine of all guns and less about anything else. 

[Curly]

How much would you increase in powder when working up a load that you are seating the bullet longer than sammi C.O.A.L.?I am working on accuracy with my rifles,Some are as much as .150 away from the lands.I realize that as I load longer I am increasing the volume of the casing,and lowering cup pressure and losing velocity.I would like to get back the lost velocity.Is there a formula that a re loader could look at to know how much pressure would be there to start,So they new that the bullet would in fact come out of the barrel?

Example:180 grain Nosler ballistic tip,IMR 4350 powder 70.grains. .300 Weatherby 26 in. barrel. Sammi seating depth is 3.533 or so,Im wanting to load out to 3.700 leaving .012 to the lands.

The best answer to your question is to run the scenario thru a reloading program like quickload and it will tell you the max powder you can use. Or you can do what most people do and just look for pressure signs and then back off.  Pressure signs sometimes only occur well over max pressure though, so maybe you could find a nice guy with quickload to run your scenario.

[Kittman]

I would be more concerned about loss of accuracy from adding more powder rather than pressure spike concerns.  When seating longer, make sure each case is miked out properly and/or properly trimmed each time for your safety.  You don't want a pressure double whammy to occur.  There are other powders that will work for that combo as well. 

[Stein]

I don't think the seating depth makes that much difference in pressure/velocity. I wouldn't adjust the powder charge at all. But if you want more velocity go ahead and increase the powder until you get pressure signs. The best tool to have is a chronograph if you want the maximum velocity possible out of that cartridge. I normally just load to the max charge in my book. But with a chronograph you would know how much you're losing with the longer seating depth. I doubt it's very much, probably less than 25 fps.

Just what I was going to say.  If you are going for accuracy, you likely won't be at max velocity anyway.  I don't even know what the sammi is for the cartridges I load.  For my rifle, I load max that will work in the magazine and for my daughter's I load to 0.01-0.02 off the rifling.

[stevemiller]

Thanks for all the replies,Now am I trying to do something that wont make any diff. in accuracy or what.It was posted that with the Weatherby it wont but I thought and I'm no pro by any means,That when you get closer to the lands it gets more accurate and when rifles get older the rifling can extend out even further from the heat and pressure so moving forward would bring an older rifle new life.  Am I way out in left field here?

[jasnt]

Do you seating depth testing first. Then work up your powder charge. Then fine tune seating depth if needed.

[stevemiller]

Ok  .Thanks.I am under the max load by a couple grains so should be fine. 

[xXLojackXx]

What bullet are you shooting? its common for VLD bullets to jump .020" to .100" in order to get bughole groups. My 7mm happens to like a .030" jump. The close I get to the rifling, the bigger the groups.

[JackOfAllTrades]

Do your seating depth testing first. Then work up your powder charge. Then fine tune seating depth if needed.

That's your best advice!  Get accurate loads (and that's why you're seating long anyway), then fine tune charge/seating within your defined accuracy range. Is another 100fps at 100yds really worth the hassle? It's a 300wym, Not a 300Rum.  Make sure that what you're loading will reliably cycle through your action. You may not want to build a single shot.. But could end up with one.

I seat out to .010" off the lands with my 30-338, for accuracy. I'm lucky to get another 100fps with the load I've worked up,  but only with certain bullets. Some bullets I've tried, I lose the accuracy when I use an identical powder/charge for the same weight, Ogive seated at the same distance from the lands. -even with a bullet that has a near same base shape and total bullet length.  So I stick to what works.  (66.5gns of IMR4350, Hornady 180gn Interlock BTSP (because they don't make the 190 any more) 3,100fps)  Yes, four - six loads on fire-formed 338win cases and I split the cases at the belt. -even with neck sizing only. So, hone your skills at recognizing pressure signs when you're max loading or extending the OACL for anything, and especially the belted magnums.

-Steve

[stevemiller]

What bullet are you shooting? its common for VLD bullets to jump .020" to .100" in order to get bughole groups. My 7mm happens to like a .030" jump. The close I get to the rifling, the bigger the groups.

This info is in my first post.Jack: im trying to tighten my groups the lands are over .150 from the book C.O.A.L measurements,my groups are 2-3 inches @ 100 yards.I want better.will putting my loads closer to the lanfds do this?Ive been told yes and no in this thread.

[xXLojackXx]

A .150" jump is pretty big. Try seating between .010" and .050" off the lands. I'm sure you'll find something you like.

[jasnt]

A .150" jump is pretty big. Try seating between .010" and .050" off the lands. I'm sure you'll find something you like.

my weatherby like .181" of jump. Your rifle will tell you whàt it likes

[stevemiller]

A .150" jump is pretty big. Try seating between .010" and .050" off the lands. I'm sure you'll find something you like.

my weatherby like .181" of jump. Your rifle will tell you whàt it likes

Ran 10 rounds thru today,I am very happy.My first 3 shot group was over (I was a little nervous)1.75 @ 100 yards my fallowing (4) 3 shot  groups at 100 yards can be covered with a nickel.My 5th 3 shot group could be covered with about 3/4 of a dime.Now with chronograph I measured every shot,I averaged 2845 fps. should i even worry about bringing that up to 3100 fps?Thanks for all the insight to this venture from everyone.

[Curly]

You should at least see if you can get some more velocity and still maintain acceptable accuracy. Otherwise you might as well have a 30-06.

[stevemiller]

Ok so I will go up 1 grain at a time and see where it goes.No pressure signs at all at this time.Thanks Curly.

[Curly]

Congratulations on the accuracy. That is always a good feeling when the groups come out like that.

[Stein]

The deer (elk, bear, moose, whatever) will not care if it is 100 fps faster or slower.  For my rifle, I ended up going with a slightly lighter bullet than I wanted just to get the best shooting round.  It is what it is, load it up and be glad when you have the cross hairs on an animal that you have full confidence knowing exactly where the bullet is going.

Going in, many people think they are going to have the bullet they want going the max speed and have under 1/2 moa.  It doesn't work like that.  Good news is that it doesn't matter if your bullet is 20 grains heavier or lighter or your velocity is +-100 fps as long as you shoot it well.

[stevemiller]

The deer (elk, bear, moose, whatever) will not care if it is 100 fps faster or slower.  For my rifle, I ended up going with a slightly lighter bullet than I wanted just to get the best shooting round.  It is what it is, load it up and be glad when you have the cross hairs on an animal that you have full confidence knowing exactly where the bullet is going.

Going in, many people think they are going to have the bullet they want going the max speed and have under 1/2 moa.  It doesn't work like that.  Good news is that it doesn't matter if your bullet is 20 grains heavier or lighter or your velocity is +-100 fps as long as you shoot it well.

I agree they would not care but 400 fps Makes quite a bit of diff. on trajectory and energy.I loaded up 10 rounds adding 1 grain to the load (71 grains now)and now get an average velocity of 2873 (didnt come up much did it) lol.No change in accuracy.

[bobcat]

The deer (elk, bear, moose, whatever) will not care if it is 100 fps faster or slower.  For my rifle, I ended up going with a slightly lighter bullet than I wanted just to get the best shooting round.  It is what it is, load it up and be glad when you have the cross hairs on an animal that you have full confidence knowing exactly where the bullet is going.

Going in, many people think they are going to have the bullet they want going the max speed and have under 1/2 moa.  It doesn't work like that.  Good news is that it doesn't matter if your bullet is 20 grains heavier or lighter or your velocity is +-100 fps as long as you shoot it well.

I agree they would not care but 400 fps Makes quite a bit of diff. on trajectory and energy.I loaded up 10 rounds adding 1 grain to the load (71 grains now)and now get an average velocity of 2873 (didnt come up much did it) lol.No change in accuracy.

Try bumping it up a couple more grains, you're still barely above 30/06 velocity. Hodgdon online shows 72.6 grains IMR 4350 as max with a 180 grain bullet. You should be able to easily reach 3,000 fps.

[stevemiller]

  yeah Im gonna go to 72 grains next 10 rounds,Still no signs of pressure.Ive seen loads as high as 77 grains with the IMR 4350 to get to the 3000 fps range so Ill just keep creeping up and watching for pressure signs.

[birddogdad]

  yeah Im gonna go to 72 grains next 10 rounds,Still no signs of pressure.Ive seen loads as high as 77 grains with the IMR 4350 to get to the 3000 fps range so Ill just keep creeping up and watching for pressure signs.

not messing with COAL, here is some insight if you consider other bullets...
http://www.longrangehunting.com/forums/f19/berger-load-data-300-weatherby-71897/
.. as long as you aren't dropping primers after the shot...

[stevemiller]

I see in that forum that this Nieko basically is doing the same as me,just diff. powder and Im out another .05 on the coal.Thanks for the link.
I didnt realize some were and some were not free bore.Mine is free bore more than when it was new I might add,I never really had good groupings with it before now,but now, wow,I am so glad I got into reloading.If your not getting what you think you should be getting out of any firearm you own,You owe it to yourself to learn it or have someone you know and trust do it for you. 

[JackOfAllTrades]

I agree that you're headed in the right direction to get some more velocity with acceptable accuracy. I would bump up 1gn then go .5gn increments until you experience pressure signs or accuracy changes, (I doubt you're even close with that 30-06 load), and I wouldn't change OACL at this point, Be happy with 3,000fps, but there's more in that gun. I don't recall, what is barrel length? Longer tube generally = slower powder.

"Mine is free bore more than when it was new I might add"  And how are you determining this?

The only shot that really matters is the first cold bore shot. Know where that hits at various ranges. But also know where the second/third warm bore shots strike. These would be rapid right after the cold bore shot. These would be the follow up shots on big game that you don't want to lose if you didn't place the first one in the boiler. (animals do move...)

-Steve

-Edit

I looked back and see that you have a 26" barrel.  I highly suggest you try Reloader 22.  (There are lot of people with Weatherby mags that use Reloader 22 with great success.)  But you'll have to work up your loads just the same as you're doing with the 4350.

[Caseknife]

I don't know if my reloading procedure is right, but it works for me.  When working up loads, I use two or three different powders that with max loads will make compressed loads, while using one bullet, ie: Barnes 150gr TTSX.  With each powder I will load five loads of four rounds each at .5 gr increments from the max load listed back down.  They are put in a numbered box, 1-5, with 5 being the max load.  I will measure the COAL of the cartridge with the specific bullet for the rifle I am loading for and load about .050" off the lands.  I then go to the range and shoot for groups, .5gr can make a big difference in group size.  I pick the best group and then load with that powder amount and vary the seating depth for the next shooting session.  It does get a bit expensive if you are working up loads with bullets that cost a buck a piece, but once you get your load that works with your rifle, you are good to go.  If I see signs of over pressure before I get to the maximum loads, I stop and pull the bullets from the cases.  Usually the best accuracy is less than the max load.