Tikka Varmint in 223 Rem

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lannie

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I decided to try the Sierra 69 gr. Match king. I am having difficulty getting
getting a consistent reading for o.a.l. to the lands. I am curious to know what anybody else came up with. Not sure but i think when i close the bolt
and then pull it back the bullet is sticking in the bore and is actually longer
oal than it should be. The readings i have had vary between 2.335 and 2.376
Most consistent is 2.348. I was using 75 gr. A max before with great results
but when purchasing bullets they were often out of them and i could see the
69's on the shelf so i thought what the heck. Maybe the more tapered 69,s
are just a little harder to get an accurate reading ? Any help would be appreciated.
thanks
Lannie
 
Cant help you with 69 gr. but I tried 80gr in my tikka and they worked great also. However you have to single load them.
 
lannie said:
I decided to try the Sierra 69 gr. Match king. I am having difficulty getting
getting a consistent reading for o.a.l. to the lands. I am curious to know what anybody else came up with. Not sure but i think when i close the bolt
and then pull it back the bullet is sticking in the bore and is actually longer
oal than it should be. The readings i have had vary between 2.335 and 2.376
Most consistent is 2.348. I was using 75 gr. A max before with great results
but when purchasing bullets they were often out of them and i could see the
69's on the shelf so i thought what the heck. Maybe the more tapered 69,s
are just a little harder to get an accurate reading ? Any help would be appreciated.
thanks
Lannie
Click to expand...

If it is sticking in the lands, load some at .010" or .020" deeper than you are now and see if it happens again. I have had OAL deviations with 80grn Sierra matchkings of about .006" and that is about the difference in length between these bullets when measured with calipers from tip to base. To get an accurate COAL reading, you must use a comparator that measures ogive to base as it really only matters where it hits the rifling.
 
What you are doing is Jamming the bullet onto the lands, that is why it is sticking. Try a little less OAL next time.

I like to 'smoke' the bullets I am using for an OAL test fit. I do this by holding a bullet (after it is seated in an empty case) over a zippo lighter, smokes the heck out of the bullet.

I measure the OAL of the round, put it in the chamber and close the bolt. Open the bolt and the round ejects. Measure the OAL again to see if its the same (sometimes it isn't). Usually you can see the marks on the bullet where the lands were contacted.

This is where the hard part comes in, now you have to 'do math' to figgure out what the OAL is (with that particular bullet) in your particular firearm.

I have yet to see 2 firearms with the same distance to the lands, even from the same manufacturer and model of firearm.

Cheers!

lannie said:
I decided to try the Sierra 69 gr. Match king. I am having difficulty getting
getting a consistent reading for o.a.l. to the lands. I am curious to know what anybody else came up with. Not sure but i think when i close the bolt
and then pull it back the bullet is sticking in the bore and is actually longer
oal than it should be. The readings i have had vary between 2.335 and 2.376
Most consistent is 2.348. I was using 75 gr. A max before with great results
but when purchasing bullets they were often out of them and i could see the
69's on the shelf so i thought what the heck. Maybe the more tapered 69,s
are just a little harder to get an accurate reading ? Any help would be appreciated.
thanks
Lannie
Click to expand...
 
If you use a case that you already fired out of the gun and a bullet that you grind down the diameter very slightly and insert into the chamber the bullet should slide back when chambered and give you and exact COAL with the bullet touching the lands. Then measure and seat the bullets in the next batch maybe 0.005" shorter to see if it likes that length.
I really don't think trying anyone else's best COAL in your rifle will do much for you as they are all different (as you know I'm sure).
 
notsorichguy said:
What you are doing is Jamming the bullet onto the lands, that is why it is sticking. Try a little less OAL next time.

I like to 'smoke' the bullets I am using for an OAL test fit. I do this by holding a bullet (after it is seated in an empty case) over a zippo lighter, smokes the heck out of the bullet.

I measure the OAL of the round, put it in the chamber and close the bolt. Open the bolt and the round ejects. Measure the OAL again to see if its the same (sometimes it isn't). Usually you can see the marks on the bullet where the lands were contacted.

This is where the hard part comes in, now you have to 'do math' to figgure out what the OAL is (with that particular bullet) in your particular firearm.

I have yet to see 2 firearms with the same distance to the lands, even from the same manufacturer and model of firearm.

Cheers!
Click to expand...

Instead of sooting the bullet I like to shine it up with steel wool, for me it works better at giving the marks on the bullet ogive. FS
 
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