I'm new to reloading, so I have a question that I hope can be answered, that has to do with overall bullet and cartridge lenght.I have a SAKO .243, that has been fed a diet of IMP 4350 powder, 87 gr. Hornady SP bullets, and a powder load of 41.5 grs, with an overall length of 2.602". The book says for an 85gr. bullet a length of 2.560", and for a 90gr. bullet a length of 2.625". How critical is overall length, and what kind of +,- tolerance should I stick to, being a tool maker I'm a stickler for accuracy.
Bullet Length
- Thread starter rossi
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I'm new to reloading, so I have a question that I hope can be answered, that has to do with overall bullet and cartridge lenght.I have a SAKO .243, that has been fed a diet of IMP 4350 powder, 87 gr. Hornady SP bullets, and a powder load of 41.5 grs, with an overall length of 2.602". The book says for an 85gr. bullet a length of 2.560", and for a 90gr. bullet a length of 2.625". How critical is overall length, and what kind of +,- tolerance should I stick to, being a tool maker I'm a stickler for accuracy.
As above, mag length is the first to determine, and then length to lands. You should determine both for your gun with each bullet - your max OAL is then the lesser of the two. Mag length can usually be easily increased by a gunsmith, and throat length too can be increased by a throating reamer.
With a bolt gun, I take a resized empty cartridge and seat the bottom of the bullet in question to the bottom of the neck, then insert it and close the bolt on it - it will take extra effort. This length is the "jammed into the lands" length. If it is less than or equal to your mag length then it is the Max OAL for that bullet, however I like to go at least 0.025" less than mag length for mag loading and feeding reasons, and at least 0.025" off the lands for reasons of accuracy (seems to work well) and feeding. I sometimes load cast bullets so that they engrave in the lands when I load them, but am aware that if I for some reason don't fire it, the bullet could remain in the bore when I extract it - not as likely with jacketed.
Pressure is increased if the bullet has little or no "run" to the lands, but is decreased if less bullet is in the case (mimicing a larger case capacity). My 35 whelen for example has a very long throat - I load 250gr bullets to 3.400" and still am 0.100" off the lands. Accuracy is good and I can safely use published max loads (and then some if so inclined, but I'm not).
With a bolt gun, I take a resized empty cartridge and seat the bottom of the bullet in question to the bottom of the neck, then insert it and close the bolt on it - it will take extra effort. This length is the "jammed into the lands" length. If it is less than or equal to your mag length then it is the Max OAL for that bullet, however I like to go at least 0.025" less than mag length for mag loading and feeding reasons, and at least 0.025" off the lands for reasons of accuracy (seems to work well) and feeding. I sometimes load cast bullets so that they engrave in the lands when I load them, but am aware that if I for some reason don't fire it, the bullet could remain in the bore when I extract it - not as likely with jacketed.
Pressure is increased if the bullet has little or no "run" to the lands, but is decreased if less bullet is in the case (mimicing a larger case capacity). My 35 whelen for example has a very long throat - I load 250gr bullets to 3.400" and still am 0.100" off the lands. Accuracy is good and I can safely use published max loads (and then some if so inclined, but I'm not).
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