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243 winchester
- Thread starter Dano4734
- Start date
I start by determining the max OAL (bullet touching barrel lands) in the particular gun I'm loading for. I then back off .020" to.030" and start with that as my OAL. There are a few ways to determine max OAL. A search should point you to a method you can use.
I've not tried that particular bullet in my 243. But in mine the max OAL for the 100gr Hornady BTSP is 2.76", where the 100gr Speer BTSP is 2.835". So the max OAL can vary quite a bit depending on bullet and chamber.
Lastly, if the OAL you are starting with is below the OAL of the load data you are using, you may want to reduce the starting charge slightly.
I've not tried that particular bullet in my 243. But in mine the max OAL for the 100gr Hornady BTSP is 2.76", where the 100gr Speer BTSP is 2.835". So the max OAL can vary quite a bit depending on bullet and chamber.
Lastly, if the OAL you are starting with is below the OAL of the load data you are using, you may want to reduce the starting charge slightly.
ligonierbill
New member
Loading mine to 2.650 over IMR-4064. Very accurate out of a Ruger American.
The Sierra manual uses 2.650" for both of their 100 grain bullets. That's a going to be a good starting point. Different gun makers use slightly different reamer designs, with the result that some throats are longer than others. Additionally, depending upon how much wear the reamer had on it when your chamber was cut, your freebore and neck area may be wider or narrower than the next rifle from the same maker had, and that affects how much gas bypasses the bullet before it gets to the throat which affects the peak pressure reached, and with that, the barrel time and point of release in the muzzle deflection induced by recoil moments and pressure distortion during firing.
I'm not trying to overwhelm you with the multitude of influences and factors that affect accuracy, but rather to give you some idea why handloaders commonly say, "every gun is a law unto itself". That just means what the next fellow's rifle likes best often does not match what your's likes best. Seating depth is certainly one of the things no two guns can necessarily be counted upon to agree on exactly. Berger has an article on this that is worth your time, having found their own VLD bullets will shoot best in some rifles jamming the lands in the throat, but in others may need to have as much as 0.150" of jump to the throat.
That said, you can generally find one load that does pretty well in most rifles. This is what Dan Newberry calls a chocolate ice cream load, based on the idea that no matter what flavor of ice cream people consider their favorite, almost everyone at least likes chocolate pretty well. So what you need is a method of finding such loads. Newberry likes his OCW method. He lists a load for 100 grain bullets of 42.2 grains of IMR 4831. The only IMR 4350 load he lists as an OCW load is for a 75 grain bullet.
I'm not trying to overwhelm you with the multitude of influences and factors that affect accuracy, but rather to give you some idea why handloaders commonly say, "every gun is a law unto itself". That just means what the next fellow's rifle likes best often does not match what your's likes best. Seating depth is certainly one of the things no two guns can necessarily be counted upon to agree on exactly. Berger has an article on this that is worth your time, having found their own VLD bullets will shoot best in some rifles jamming the lands in the throat, but in others may need to have as much as 0.150" of jump to the throat.
That said, you can generally find one load that does pretty well in most rifles. This is what Dan Newberry calls a chocolate ice cream load, based on the idea that no matter what flavor of ice cream people consider their favorite, almost everyone at least likes chocolate pretty well. So what you need is a method of finding such loads. Newberry likes his OCW method. He lists a load for 100 grain bullets of 42.2 grains of IMR 4831. The only IMR 4350 load he lists as an OCW load is for a 75 grain bullet.
"...most accurate depth that others use..." No such thing as every rifle is different. The 2.677" is fine though. SAAMI Max OAL(Isn't a 'depth'. It's a loaded length, measured from the end of the bullet to the flat of the case.) is 2.710".
Only ever loaded Speer 105's myself. I'd have to look at what OAL, but it doesn't apply to every rifle anyway. Probably the 2.710".
"...holes were touching..." Stop fiddling with any of it. You're done.
Only ever loaded Speer 105's myself. I'd have to look at what OAL, but it doesn't apply to every rifle anyway. Probably the 2.710".
"...holes were touching..." Stop fiddling with any of it. You're done.
You may have found what shoots best with your first try . Just because it shoots good in one rifle doesn't mean it will shoot good in all. If we bought the same rifle make , model & caliber . Yours may shoot better with to bullet jammed , mine may shoot better jumped. That's the fun in reloading. Just remember bullets change with every lot number . Know where the measurement is when the bullet touches the lands , from there you can jump or jam your loads for whatever works best in your rifle.