Printable View
Is there a "rule of thumb" on how much bullet should be seated into the case
I.E. a .0308" bullet in a 3006
I've heard, but never heed, depth should be equal to the diameter. 0.308" would be 0.308" not counting the boat tail
Or maybe just 0.02" from rifling--In a particular 3006 that only lets 0.167" in case neck
Thanks...BCB
BCB
This would be my procedure for a hunting round.
Using the 30-06 cartridge as an example. First, make up a dummy round ( no primer or powder). I seat the bullet shallow, then chamber to check and see if the bullet bumps the rifling. If it does, I bump it deeper until the rifling mark's disappear. You can also use a modified Stoney Point case, if you want to be real critical with the bullet just clearing the rifling. This can be made easier to see the rifling marks, if you take a sharpie and cover the ogive. The next step, I check to see how much bullet shank is seated into the case. As you stated, I seat the bullet to at least one bullet diameter. Lastly, I check to see how the round clears in the magazine. If the cartridge is to long, I bump the bullet deeper until the cartridge fits the magazine. If all is fine, I make my reloads to match the dummy round.There are many different techniques used, this is just one of them.
For single shot, or bench shooting
targets, I seat the bullet about .010 short of touching the rifling, providing the bullet shank is seated deep enough to suit me. In this case, longer bullets work best, with the bullet clearing the rifling, and plenty of shank seated in the case.
Regards.
^^^this^^^^
I write all around the bullet nose with a sharpie so I can see the rifling marks easier too.
There is no "rule of thumb" . Some folks say you need a full caliber of length of bearing surface in the neck ,that is a myth . Too many variables involved to throw a blanket statement over proper seating depth as a rule . As long as you can get your bullet to stay straight in the brass you are OK .
Neck tension or lack of along with jump/jam to lands also play a major role in accuracy . This is for single feed, if feeding from a magazine it is a whole different story .
The "blanket statement" issue is further complicated by rifles like my Rem 700 -06 (and from what i understand some high end rifles like Weatherbys), it has a long throat/leade, most "normal" spitzer bullets for the caliber can be barely seated in the case and still not touch the lands, boat tails are even worse. It shoots the best with long, fat, flat based bullets. My buddy has a bore scope and it was cut that way, the barrel is not worn/shot out as the tool marks are still visible.
Correct seating depth is the key to unlocking the accuracy potential of any rifled firearm. I've been reloading since I was a kid, and being a Pennsylvania groundhog shooter caused me to strive for the best accuracy possible. I tested every variable to see what would give me the best accuracy. Different bullets, powders, primers, cases, charge weights, you name it. Sometimes a load would give decent accuracy, but for whatever reason the results wouldn't hold up over time. I became frustrated because I was doing everything everybody said to do and I wasn't getting the consistent accuracy I wanted. Then one day I happened upon an article by Layne Simpson in the Nosler #3 reloading manual where he explained bullet seating depth and the affect it had on accuracy. For the sake of brevity I won't go into everything he said here, but you need to free-float your barrel, get your scope cinched down tight, and determine what seating depth your gun prefers. To do the latter you need to be able to measure precisely where the ogive of your bullet is, and then seat those bullets at a consistent depth. The article is well written and he explains everything step by step. If you are interested in achieving the best accuracy for your firearm I highly recommend getting a copy of the Nosler #3 manual and checking it out. Good luck!
For best accuracy with jacketed bullets I've found over the years shooting both long range matches and varmints that best accuracy comes with the bullet just of the leade (rifling) by a couple thousandths. That work ok if single loading but if loading from the magazine then OAL and crimping come into play. With such I seat to the OAL of the magazine that give reliable feeding. If crimping for tube feeds or gas guns then you are restricted to seating to the crimp groove/canalure.
With cast bullets I prefer the GC or base of the bullet not to extend below the neck. I also prefer the front of the drive band to slight engage the leade. That helps centering the bullet concentric to the bore. However, with some rifles and bullet designs [most notably those bullets with a meplat, especially a wide meplat] if fed from the magazine feeding reliability can become a major issue. With those the seating depth can sometimes be adjusted to increase reliability. With many of those rifles with staggered box magazines I find them to be "two shooters" at best with one up the spout and one in the magazine. In many milsurps with long actions many cast bullets can not be seated and stay in the case so the front drive band reaches the Lead. With tube fed actions, again, the bullet is seated to the crimp groove and crimped.
Lots of compromises to be made regardless so one "rule of thumb" does not necessarily fit all.
No rule of thumb that works.
Long OAL may not allow powder to burn correctly. The rounds may get crooked from handling.
I have several rifles that need seated deep into the case, due to magazine length. For those, I try to use a mold that fills the throat, rather than contact the lands. For my rifles with enough space in the magazine, I have rented throating reamers from Pacific Tool & Die, and lengthened the throat. It doesn't take much, so make a cut, and check!
im lazy i seat boolits so the fit the mag and chamber easily .
With cast boolits ... we are talking cast boolits right ... I seat to the boolit's crimp groove .
Then I see if they fit into magazine , will feed from magazine and check to see if they will easily chamber .
So far ... So good !
I only have 5 different 30 cal. moulds and one 303 mould but to date my method has worked with every boolit in 30-30 Win. , 30-06 Springfield , 308 Win. , 7.5 Swiss and the one 303 British .
Maybe not as technical as many would like it but the owner of the gun shop , when giving me some reloading instructions and advice , said keep it simple and don't overthink it ... the crimp groove is there for a reason .
Gary