fellas i have been loading for my ar-15 and until lately have just been loading to max mag length which is 2.835" with my stoney point comparator. I have been loading 50gr NBT's and have figured the max oal at 3.013" with my comparator but when i load past 2.95" my bolt carrier wont close and there are long scrapes from the riflings in the bullet jacket. What is wrong? I have heard some guns like bullets to be seated deep is this true?
whats going on
- Thread starter craiger40
- Start date
If you have rifleing marks on your bullets then you are seating too long. You are simply seating the bullets so the bullet is in the rifleing when the chamber is closed, that will increase chamber pressure and make a mess when you lodge a bullet in the barrel after trying to eject a loaded round.
craiger40":z9kqytds said:
How do you get a 2.95" COL with the 50 gr BT and keep the bullet in the case? I load mine for my M70 HV to 2.385" col with the same bullet and only have .165" of bullet shank in the neck, part of that is the boat-tail taper so contact is even less.
The max SAAMI lenght for the 223 is 2.26". Some rifles are long for cartridge in the magazine, some in throating. The mag may hold a longer round but the throat is also a factor in the max OAL one can load to. The throat along with the magazine will vary from rifle make to make and both have to be taken in consideration when setting your lenght.
I`d measure the lenght of the rifleing marks on the bullets you have tried chambering and subtract at least that much from my OAL and try chambering a dummy at that lenght. Color or soot the bullet (I use magic marker) and see if the rifleing is still contacting the bullet, the ink will mark from the rifleing, if so seat deeper if not record and try that OAL for function and accuracy.
Keep in mind a semi auto is very rough on ammo when feeding. The std rule of thumb that a bullet should be seated one (1) caliber deep at the least in the case neck should be followed in loads for them. If there is not enought neck tension on the bullet they can be driven deeper in the case by the action when the high speed bolt slams in the base of the case or the bullet contacts the chamber while being driven forward. A crimp can also help hold the bullet, and a lot of reloaders use one on their ammo for semi auto firearms.
A Stoney Point chamber gauge in addition to the comparator would be a very helpful tool to pick up. I use both when setting the lenght of a cartridge for my rifles and recommend them. The ink or soot method works, but the Stoney point is much, much, faster. You can see one at work here,
http://billmcmichen.home.mindspring.com/StoneyPoint.htm
- Thread starter
- #4
I have and use a stoney point comparator and OAL gauge and use to two in conjunction. i measured my MAX OAl for the 50gr NBT more than a few times an alway get 3.013 inches. My numbers are absolute max that is the bullet is touching the rifling then i back off. remember that when you put the comparator body on the caliper it adds over an inch to the caliper zero, All my measurements include that excess. You are right about seating the bullet deeper however if needed i would load each round individually. Iam more concerned with accuracy in this load than fucntion in imy autoloader . When useing a comparator even mag length loads in my rifle are longer than 2.26"
OK sorry, I wasn`t aware you were including the comparator body in your measurment. I normally subtract mine and take it for granted everyone does I guess 
Have you tried shorter AOLs in your rifle? I have seen in a couple of mine the best accuracy doesn`t always come at the lands or even in some cases near it. The old 6.5x55 Swede BBl I had on a Mark X like the bullet almost a full 0.10" off the lands, and my 7-08 prefers a jump of as I remember ~ 0.035"+. (I don`t have my notes handy)
A Winchester High Wall I have in 223 won`t let me within 0.1" of the lead with bullets like the Nosler BT or Hornady V`max and still have them in the case. It shoots 1" or better with 55 gr Nosler BT`s base at about 0.030" deep in the case, the 50 gr I seat with the base of the bullet close to the shoulder/neck junction..Longer COL and the groups open, go figure :?
At any rate if you have rifleing marks on the bullet you`re too long and need to reduce the OAL to compensate for it. Only experimenting with the OAL will tell you where the rifle prefers to have the bullet. I`d go as long as possible while avoiding the lands, loading 5 rds in - 0.005" increments down to =0.030"/ -0.035" and see which lenght the rifle seems to like. When you get an idea of the best OAL load another 5 rds at that lenght and 5 rds at 0.005" longer and shorter to verify the rifle truely prefers that lenght.
Have you tried shorter AOLs in your rifle? I have seen in a couple of mine the best accuracy doesn`t always come at the lands or even in some cases near it. The old 6.5x55 Swede BBl I had on a Mark X like the bullet almost a full 0.10" off the lands, and my 7-08 prefers a jump of as I remember ~ 0.035"+. (I don`t have my notes handy)
A Winchester High Wall I have in 223 won`t let me within 0.1" of the lead with bullets like the Nosler BT or Hornady V`max and still have them in the case. It shoots 1" or better with 55 gr Nosler BT`s base at about 0.030" deep in the case, the 50 gr I seat with the base of the bullet close to the shoulder/neck junction..Longer COL and the groups open, go figure :?
At any rate if you have rifleing marks on the bullet you`re too long and need to reduce the OAL to compensate for it. Only experimenting with the OAL will tell you where the rifle prefers to have the bullet. I`d go as long as possible while avoiding the lands, loading 5 rds in - 0.005" increments down to =0.030"/ -0.035" and see which lenght the rifle seems to like. When you get an idea of the best OAL load another 5 rds at that lenght and 5 rds at 0.005" longer and shorter to verify the rifle truely prefers that lenght.
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- #6
I have actually just finished some loads shortining the length.I have been told that shorter sometimes worked best. I wanted to try towards max length just because thats seems to be the thing to do to find smaller groups. After more thought i decided not to mess to much with it too much because the first loads were at MOA and i probably just needed to do better on my part shooting. The chrony indicated that i was really close to Nosler load data so i may just fine tune this load. Any other ideas to try would be greatly appreciated. I dont subtract the comp body just for simplicity but if the standard is to do so then i should do so in the future.
