Sierra Match King Assorted lengths ? Whats WRONG?

358Scout

358Scout

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I loaded 25 rounds of 243 Winchester in my new Lapua brass. Used my new Redding competition seating die and set it to a C.O.A.L. of 2.850" base to bullet tip. This O.A.L. was determined by the Gunsmith who chambered the barrel using the loaded cartridge I gave him. Case lengths are all the same. Powder charges were each weighed. I measured the COAL of each and determined a big variance between 2.843 to 2.850. Keeping the cartridges separate I went to the range to see how they grouped. Starting with the 2.850 as the first string, I ended up with a 4 shot group measuring .221" & 100 yds. After that it went all to pot with 1.25" out of two groups. Came home and measured my Sierra 107 Match Kings. Are they supposed to be different lengths? I grabbed 7 out of the box. Measured lengths varied from 1.214" to 1.224". Am I supposed to trim them down? Either that or I'm doing something wrong.
Any ideas?
 
sounds like some bad quality control to me, i could see the lead tipped gamekings to be different sizes due to the lead deforming, but not the matchkings:confused:
 
It's just the way the tips end up when the bullet is formed, there is a trimmer you can buy to make them all the same if you want. Seven thou isn't a huge varience of the OAL from the tip, the important measurement is from the ogive to the base.
 
Get a comparator and set the OAL once for the competition seater and just check the odd one to see if they are still the same. The SMK tips all vary and is not a very good way to measure COAL. You need to measure off a known point - ogive
 
Any bullet base-to-tip dimension is going to show variance. As mentioned, without using a bullet comparator to check ogive-to-ogive measurements, 'precision' is just pissing into the wind here.

-M
 
1. Get a neck-sizing die (or swap out a slightly looser bushing in a bushing die).

2. Make a 'dummy' round where the bullet will require just a hair of hand-tension to move back and forth, but will be retained positively when it's moved around. Just enough tension to hold the bullet so it won't move when taking it from chamber to calipers.

3. Push a bullet in by hand, just far enough to have it held - this round should look "stupid long."

4. Chamber the round.

5. Extract the round - GENTLY - and measure it with the bullet comparator setup. GENTLY.

6. Record, then pull the bullet out to the "stupid" length again by hand.

7. Repeat 4, 5, 6 as many times as you feel you need to (3+) to obtain a reliable OAL-to-the-ogive measurement for your chamber.

-M
 
SMK do vary in length but as long as you are seating them the same they will work. If you are using a Redding competition seating die the ogive will be the same. I suspect the larger groups are pilot error.
 
The tools you need are a Hornady OAL Guage, a comparator, and the comparitor insert that matches your caliber...and a decent digital caliper.
 
I measured an entire box of 175gr SMK's and found variation of .030 longest to shortest. I emailed Sierra and they told me that a variation on .015 to .020 was normal, and I should only notice slight vertical dispersion at ranges of 500 yards and up. So I just grouped them together into lengths within .005 and shot those together in groups. Seemed to work fine.

I measured 50 rounds of Nosler 130 gr .277 balistic silver tips, max variation was .003....hmmm
 
Sierras are all like that.
I Weight sort them and shoot them.
They are quite capable of bughole accuracy just as they are.

After you seat a bullet you must measure off the bullet ogive (use a comparator). Measuring off the bullet tip will lead to madness. :)

If you are shooting competition Hornady A-max, Berger, and Lapua bullets all offer much better quality control.

Quite surprisingly this may or may not equate to better accuracy....Go figure!
 
JEC said:
The tools you need are a Hornady OAL Guage, a comparator, and the comparitor insert that matches your caliber...and a decent digital caliper.
Click to expand...
358Scout,
Read JEC's post again..
Anybody who doesn't have and use the tools above for making match type ammo is just farting in the wind or are doing it the hard way...
I don't know who sells the above tools in Canada, maybe JEC does..
I buy my reloading measuring tools from Sinclairintl.com
Get their catalog and you will be like a kid in a candy shop... They ship to Canada and usually have their product in stock..
Sorry if I sound blunt... I'll leave it at that.
 
There is a six sided tool out there called a "NUT". It has holes of different diameters on each flat. It is used to measure ogive length and OAL cartridge length. Its cost is around $10. It is simple to use with either a 6 inch vernier or micrometer.

It measures off the ogive, rather than the bullet tip.

If you've ever swaged your own bullets, you will notice a bit of variation in bullet lengths. It doesn't seem to hurt anything. I used the home swaged bullets for Hunter Bench Rest and never had an issue with any of them. The important length is the ogive dimensions.
 
bearhunter said:
There is a six sided tool out there called a "NUT". It has holes of different diameters on each flat. It is used to measure ogive length and OAL cartridge length. Its cost is around $10. It is simple to use with either a 6 inch vernier or micrometer.

It measures off the ogive, rather than the bullet tip.

If you've ever swaged your own bullets, you will notice a bit of variation in bullet lengths. It doesn't seem to hurt anything. I used the home swaged bullets for Hunter Bench Rest and never had an issue with any of them. The important length is the ogive dimensions.
Click to expand...

I have both sets of the 6 sided nut, it came to me as the Sinclair Comparator, about $18.00 usa money. FS
 
Great! Picked up a comparator at the gun show. Took one case and made 3 spits in it neck and shoulder. Seated a bullet and slowly chambered it locking the bolt and than again slowly extracted the cartridge. Measured the base to ogive with a comparator - did this 15 times. This gave me an average of 2.162". Think I will start with a seating depth of 2.160". Thanks again - this sure helped
 
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