What am I doing wrong?

[HeathSexton]

I have been trying to load for my .243 and I made a dummy round by sizing a piece of brass and cutting the neck so I could slide a bullet to find OAL. After chambering and measuring 10 times I found my OAL and loaded a few to test tomorrow. Using my Hornady comparator I measured my dummy round and it is consistently .009" shorter than my loaded rounds, every single time. My loaded rounds are all within .001" according to my comparator so they all loaded up the same. I made another dummy round my lightly sizing the neck and it measures .009" shorter than my loaded rounds.


Thoughts?



Thanks

 

[shoots_5]

Maybe the primer is sticking out that .009" on the loaded rounds if the calipers are going across the primer pocket? That's the only thing I can think of....

 

[HeathSexton]

I took a piece of sized but not primed brass and seated a bullet, it is .009" longer than the dummy rounds also.

 

[JD338]

Are you using bullets from the same lot?

JD338

 

[HeathSexton]

Yes, same lot.


So far accuracy has been horrible with IMR4350 and a 100gr BTSP.

 

[Duncan]

by chance are your loads at 100% capacity? and you are not compressing the loads down far enough. it seems the loaded rounds are the only ones doing this. something to look at.

 

[HeathSexton]

Plenty of room for powder, IMR4350 is the powder from 39-43grs in .5gr increases and the best I have got is a 1.5" group. This is an accurate rifle so I know it can shoot.

 

[rick smith]

Use your comparator to measure the unseated bullets. Seating pressure can change measured seating depth, the pressure and speed you place on the press handle. Neck thickness, uniformity and amount of neck tension will also effect seating depth. Using the split neck method works as long as you don't pull the bullet out part of the way as it is extracted, blacken the bullet before inserting it into the case.Rick.

 

[HeathSexton]

For those of you running 95-100gr bullets in the .243, are you setting your OAL at say .010" off for an example or are you going by book OAL? If I set mine .010" off my OAL is 2.977".


Sierra is 2.65", Hornady 2.63, Nosler 2.7

 

[HeathSexton]

I finally got things worked out I think. 42.3grs IMR4350 showed some good groups and a friend called and wanted to get some distance shots. We put up a steel buffalo the body is 10.5"highx22"long and ranged it at 617yds. I only took 9 rounds but I went 5 for 9, the first 3 were misses because we were having to guess at velocity because my chrono died and I was trying to dial the drop. I was pretty pleased because I have never shot that far before. I am heading back out tomorrow with more ammo. I had to dial up 14" to hit at 617yds.