OAL or Charge Weight

[MrJames680]

What is better? Find the most accurate OAL first then find the best charge weight or vis-versa? I have read some articles that say finding the best OAL first is better when developing a load.

[stimpylu32]

I always start with the listed O A L and very my powder charge till I find the best load , once that is done , then I start to tweek the O A L , just the way I started and it works for me .

Some guys will set the bullet .010 off the lands and only ajust the powder charge , I like having as many options as I can get . 

stimpy

[mjbgalt]

yep, stimpy, i do it the same way.

to me the overall length is more of a constant than the charge. i find an OAL and then work with the charge weight. if NOTHING works i change the OAL and start again.

-Matt

[Autorim]

I always start with OAL. I just loaded some 9mm test rounds with 4 different bullets in three weights. OAL different for all. OAL is usually determined by the max the magazine will accommodate, but max OAL may be reached in some guns due to contact with the rifling. In revolvers, I seat to crimp in the crimp groove.

[gofish]

+1 for OAL first.

[Bullseye]

I am a little different.  I always load to the book OAL and vary the charge weight.  I have always been able to get the accuracy I want by varying the charge and using the book OAL.  But then again I am happy with MOA out of any gun caliber combo that should be that good and do not try for benchrest accuracy.

[AtlLaw]

I always load to the book OAL and vary the charge weight.

This is what I basically do or, if circumstances permit, I measure with an OAL gauge and start with the bullets seated around .030 off.  Then when I have my base load developed I may play with the seating depth.

[Land_Owner]

+5 for fixing Mfg. OAL and varying charge weight.

[SHOOTALL]

I match a factory loaded bullet of the same construction and weight sometimes , sometimes i seat the base of the bullet even with the base of the neck , if the bullet has a crimp grove i try it first And sometimes i seat almost touching the rifeling . I haven't used the force yet .
Guess you could say i don't follow a plan every time .
Oh yea powder I will admit i start near max in most cases ( SPEED KILLS ) . But to be honest with a bad shoulder i have been backing off some as late . but that is always a second thought.

[MrJames680]

Hmmm, I dont know. It seems to me that either way, you will eventualy come up with your best load. Correct me if I am wrong but, charge weight has more to do with barrel harmonics and the time the bullet leaves the crown. OAL has more to do with initial bullet stability when leaving the case/entering the rifling, although the OAL does have some effect on when the bullet leaves the barrel. (.243 Win Handi)

I am pulling off just over 1.3inch groups at 300yrds.  For my purposes this is more than good so I think that I will call it quits on this load and move on to something else. I have put a LOT of time into accuratizing my rifle with factory ammo first. I am currently reloading with 55gr bullets and then plan to start a load using the Varmint Grenade or VMax (both?  ) I was thinking of trying out OAL first to see what happens. I believe that these projectiles are a bit longer so I would be able to play with OAL. All my 55grainer have been mfg-oal. The most accurate charge weight was just under midrange. I have no need for speed, just accuracy.

I figure that so far that as a newbie reloader I am doing it right so I may as will log that load in the books as good and then play with my next variant.

[Autorim]

I guess my point is that the SAAMI specifications for OAL is adhered to by ammo makers and the firearms are manufactured so that the ammo will function in them. This is great, but throating can - and does - vary a lot. That is why I check for OAL first. I have had rifles that were throated so long that a bullet that engaged the rifling would not reach the case mouth.

OAL is just another part of the equation to an accurate load in a particular rifle. In a hunting rifle, OAL should always be a matter of cycling from the magazine and not being so long that the bullet engages the rifling when chambered. It is possible to attempt to extract a round only to remove the cartridge case, spill the powder in the magazine and leave the bullet stuck in the barrel.

[SHOOTALL]

OAL along with crimp can effect the first pressure spike , which to a point effects how long a bullet is in the bbl and vibration of the bbl.

[Robert357]

Hmmm, I dont know. It seems to me that either way, you will eventualy come up with your best load. Correct me if I am wrong but, charge weight has more to do with barrel harmonics and the time the bullet leaves the crown. OAL has more to do with initial bullet stability when leaving the case/entering the rifling, although the OAL does have some effect on when the bullet leaves the barrel. (.243 Win Handi)

If you read up on the ladder work up method, which is all about utilizing barrel harmonics to benefit accuracy, the masters suggest charge weight variation should be used to find a sweet spot first, prior to varying OAL. 

My personal experience is like that of another poster and that is to measure a "max" OAL and then back off one of the classic distances such as suggested in the Hornady Reloading manual and then do a ladder work-up on charge weight and after establishing a powder sweet spot based on barrel harmonics, then do a ladder test on OAL to find a "double sweet spot."  This will give you a load where there is very little change in accuracy for random minor variations in powder weight or bullet seating depth.

My pesonal expeience is that powder weight is more significant than OAL, but that may not be true in all rifles.