Sorry, one more ? on reloading (OAL)
First of all, I am loading a 270 150 grain sierra spbt bullet. When looking up the OAL, I get different numbers. In the Lyman manual it seems to be just based on bullet type and grain. But, with the Lee data sheet it seems to be based on powder types as well. Lee recommends a min OAL of 3.065 for 150 grain jacketed bullet using h4350. But Lyman gives a OAL of 3.28 for 150 grain jacketed sp. Which one would be correct or is the Lyman the max and the Lee the min? Also, would the OAL be longer with a boat tail bullet because in the Alliant manual, using alliant powders, and my exact same bullet, it lists the min OAL in the 3.3 range. So basically, I am asking if OAL is that critical and how does one know which one to use, given the variations. Thanks again for all your help, I am almost there completing that first round.
"To be prepared for War is one of the most
effectual means of preserving peace"-George Washington
"To be prepared for War is one of the most
effectual means of preserving peace"-George Washington
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Hello G.F. ,The way I determine OAL is to seat a shallow seat a bullet,chamber the cartrige(complete lockup.Then set my die for a small fraction deeper(so the bullet does not quite contact the rifleing).The confusion about the varius OALs is usually explained by the different shapes of bullets the same weight.Good Luck,Roger 0 -
garandfan, OAL is going to vary with each bullet used in your rifle. Determine the seating depth to barely have the bullet contact the lands of the barrel. Generally this helps accuracy in most every rifle. The reason this helps accuracy is because the bullet is already aligned with the bore at time of ignition rather than having a dead space between the case and the bore. All be it it will be a small distance, having the bullet seated to deep it possibly contacts the rifling off center and accuracy suffers. Use a sized case with no primer and when you find the right depth for that particular bullet, write the measurement on the case and store that dummy round in your die box. The next time you want to load that bullet use the dummy round to set your die. GHD 0 -
I read your post several times. I'm not trying to be critical here, but I do have some questions after reading your post. This is because I was always under the impression that when I was working on a Dodge truck, I wasn't able to get much information from a Ford Car Manual.
You say your are using "Sierra" bullets, yet you are looking for information as to how these should be loaded from a "Lyman" manual and from a "Lee Manual." Now, I know these two reference guides provide a great deal of valuable information, but, I question what they might say about a competitor's products......if they knew.
If it were me, I would be calling the Tech Line at Sierra because I would be thinking they might know more about their own components. What I'm seeing here appears to be a problem between distinguishing a tree from a forest......
There seems to be a very good information in the responses to your questions. Why not get Sierra's point of view?
Fish Shudder at the sound of my Name!0 -
While the above methiods are good for accuracy, your magizine length can enter the picture for hunting ammo.
With some chamberings it is imposiable to get the bullet out to the rifling and still have any part of the bullet in the case. IE: 30-06 throats are so long that a factory 220grRN is still away from the rifling, there's no way that you can set a 150 boattail out enough to get close and still be in the case.
Now the reason that long seating helps, almost all chamber specs. call for a 1.5deg/side taper in the throat area (funnel effect) which can allow the bullet to enter the rifling (somewhat) sideways. Getting the bullet out as far as possiable reduces the amount of alignment error, increesing the accuracy potential.
A few chambers (and some nutcases like me) specify that the throat have parallel sides that are a just over bullet diameter, which eliminates any chance that the bullet will be mis-alligned with the rifling. IE: my 30-06 while having enough throat length (freebore) to handle any factory load safely, I specified a throat that is .3085 in diameter starting at the end of the case cut. Which means that the bullet is in perfect alignment with the bore as soon as it is chambered (the bullet itself is acting as a centering devise).
As far as manual OAL specs go, the true dimention of concern is the distance from the bullets max. diameter to the rifling. The bullet makers know where they spec. this point on their bullets, which is why I recogmend using the bullet manfactures data. Measuring to the tip is of concern only as far as magizine length goes, and than I set mine out to .025 of maximum for that rifle.
Some guys like a mag full of lead, I still prefer one round to the head.0 -
Thanks for the help, I will probably give Sierra a call. Thanks again.
"To be prepared for War is one of the most
effectual means of preserving peace"-George Washington0
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