As someone who is just getting into reloading for my Tikka T3 6.5x55, I am hoping you can give me some insight into a couple questions:
I have some berger 140 VLD loads that were worked up by Copper Creek at 3.138 OAL. They are accurate but the velocity is a little low (2525) which is why I have decided to begin reloading myself.
The published OAL is 3.15"
I purchased a Frankford Arsenal OAL kit and got an OAL of 3.126 with the bullet touching the rifling. I then bought more sturdy rod stops since the franklin ones are not the strongest/most sturdy and measured again...very consistent @ 3.128.
The Copper creek ammo does not show any pressure signs but appears to be loaded a little conservatively based on the velocity.
When closing the bolt there is a some tension but the bullets do not show signs of the rifling digging in. There is just a faint a line that shows up in the brass on the shoulder if I fully chamber a round....snug but not excessive. No issues ejecting the rounds (either fired or unfired). After firing the rounds, about 1/3 of them have a small ding.dent right on the shoulder (see pic on next post)
1) What are the odds of having a rifle with the OAL below the published OAL. I am simply questioning myself as I am new at this and want to make sure I am not doing something wrong.
2) What would cause the small ding/dent on roughly 1/3 of the fired brass?
The dings look like what happens when an unburned powder granule in the chamber from a prior shot irons a dent into the outside of the next round fired.
The dings look like what happens when an unburned powder granule in the chamber from a prior shot irons a dent into the outside of the next round fired.
Thank you. That makes sense as to why it is only a small population of the spent brass.
You're headed the right direction. The Copper Creek velocity does sound a little conservative and I'd bet you can find accuracy at a higher velocity.
Sounds like you might want to bump the shoulder back just a hair more, maybe .001". You could use a shoulder bump gauge, but you can accomplish the same thing by the way the brass feels when chambering it. Just remember we are talking about TINY adjustments when screwing down the sizing die. With those coarse threads, it just doesn't take much of an adjustment to move the shoulder .001". Personally, I use both feel and measuring with a bump gauge. That gives me a little more confidence that I am not sizing my brass down too much, which can lead to excessive headspace and early case failure.
The published OAL doesn't really have much to do with anything in terms of precision reloading. Just a number that was established by SAAMI once upon a time. Nowadays most manufacturers design so their rifles will feed at that length, but they seem to put little thought into how far a bullet will be from the ogive. With a factory rig, if you are lucky, you may be able to reach the lands at magazine length. When having a custom barrel fitted, you can spec how long the freebore will be so that you can reach the lands at magazine length.
If you cannot reach the lands at magazine length accuracy can often still be found at some shorter length. Just systematically check different seating depths until you find the best accuracy. Berger Bullets has an effective method for doing this on their website.
Mathman addressed the dents on your brass. Cleaning your chamber may verify that.
John
If my people, who are called by my name, will humble themselves and pray and seek my face and turn from their wicked ways, then I will hear from heaven, and I will forgive their sin and will heal their land. 2 Chronicles 7:14
My T3 swede has a tight chamber. I have to cam the lever pretty hard with RCBS dies. I switched to Redding, and usually use S-Type neck dies. It won't even chamber most WW brass, so I am using Lapua.
I played with a lot of loads in mine, and found 120-123 provided the best accuracy and velocity combo. 140's were dogs in my rifle, hovering around 2650 or so. I am 2900+ with 123's.
It sounds like a tight factory chamber or the CC loads are not sized correctly.
BTW, Quickload estimates 2800-2895 using a 140 Berger Hunting VLD at 3.126, 24" barrel, 55K psi using the top rated powders (top velocity at near 100% fill).
Hondo is right. Just size a bit more, until you get no resistance to bolt closure. The only reason for the book OAL is for ammo that will fit every rifle ever made. You are customizing for your rifle, so ignore it. I never care about factory OAL.
