I've recently purchased the Hornady/Stoney Point COAL Guage set with bullet comparator. I measured the COAL and chamber dimensions on my brand spanking new CZ550 .270Win.

SAAMI Specs .270 Win 3.340 in

Sierra 130 gr. Gameking: MAX Length is 3.300 exactly, NOT 3.340. This means I am short 0.040 for SAMMI specs right? I measured this 12 times and got the same dimensions using 3 separate bullets.

Hornady 130 gr. SST: MAX Length is 3.400 exactly. I measure this 12 times and got the same dimensions using 3 separate bullets. So the round would be 0.060 long right?

I thought I understand that chambers of factory type rifles are made with a little oversize ....but I was surprised to find that using the GAMEKING I would have been 0.040 long and prolly jammed into the lands thereby raising pressures if I made the round to SAMMI specs. I would have been OK with the Hornady's. I know that ogive's of bullets do vary and so using the comparator and correct inserts...measuring to the ogive's of both bullets? They measured the same.

What gives? Am I messing up here using the tool since I am new to using it? Is my chamber outta whack, tight chamber, etc.? I believe I will be OK because I will reload using the ogive's. But this could happen to many other type of bullets, right? What sort of safety issues are there? NOW I know one of the reasons we load low and work up.

Renegade

in theory?
If you are comparing to sammi specks you will not be close.
If I understand you.. need to Measure you oal to the lands of the chamber for you rifle.
Using a case and the bullet that you plan on loading.

SAAMI COL is nothing more then the max lenght that will fit in any magazine. Your COL will differ as you found, don`t sweat it.The max COL I have in my 270 useing 130 gr SSTs is 3.20"/+ ~0.005". The manufactures cut the chamber throat to whatever lenght they feel is needed to satisfy their legal dept.

quote:

The manufactures cut the chamber throat to whatever lenght they feel is needed to satisfy their legal dept.

Or give the most regrinds of their chambering reamers.....

quote:

Originally posted by RenegadeRN:

SAAMI Specs .270 Win 3.340 in

Sierra 130 gr. Gameking: MAX Length is 3.300 exactly, NOT 3.340. This means I am short 0.040 for SAMMI specs right? I measured this 12 times and got the same dimensions using 3 separate bullets.

Hornady 130 gr. SST: MAX Length is 3.400 exactly. I measure this 12 times and got the same dimensions using 3 separate bullets. So the round would be 0.060 long right?

I thought I understand that chambers of factory type rifles are made with a little oversize ....but I was surprised to find that using the GAMEKING I would have been 0.040 long and prolly jammed into the lands thereby raising pressures if I made the round to SAMMI specs. I would have been OK with the Hornady's. I know that ogive's of bullets do vary and so using the comparator and correct inserts...measuring to the ogive's of both bullets? They measured the same.

What gives? Am I messing up here using the tool since I am new to using it? Is my chamber outta whack, tight chamber, etc.? I believe I will be OK because I will reload using the ogive's. But this could happen to many other type of bullets, right? What sort of safety issues are there? NOW I know one of the reasons we load low and work up.

Renegade

Cartridge OAL will vary according to the bullet and there is a separate listing for each one. The Sierra listing for the 130 gr Spitzer BT and the 130 gr Spitzer is 3.300", so your measurement was right on. For the Hornady the listing for the OAL is "C.O.L. - 3.275" for the 130 gr bullet. Don't know why you got the measurement you did.

Nosler manual only lists the COAL at the beginning of each caliber listing and it shows 3.340" as you stated.

In the manuals it looks like Sierra, Speer and Hornady lists a separate COAL for each bullet weight and contour. Nosler and Barnes do not list separate COAL's just the one for each caliber (don't know how that would work).

Hey, if you are getting consistant readings then you are doing very well indeed. The Hornady (Stoney Point) OAL Gauge takes some practice and not all of us are capable of leaning to use the "thingy", right H C?

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Originally posted by woods:
...The Hornady (Stoney Point) OAL Gauge takes some practice and not all of us are capable of leaning to use the "thingy", right H C?

Other than an obvious Typo, that is a true statement.

Here is the sentence corrected - "The Hornady (Stoney Point) OAL Gauge takes some practice(EDIT IN: To toss it far enough away that you can not find it. This is preferably done from a boat.) and none of us are capable of leaning to use the "thingy",(This next "implied" portion is so obvious that the reader should already be aware of it.) with the same level of precision accuracy which is attainable with the ancient-old, time-proven, never-fail, consistently-repeatable, Cleaning Rod Method.

Always glad to hep ya out Woods.
-----

Come to think of it, Woods highly exhalted and esteemed buddy "BH" might consider contracting his services as a "Thingy Tosser" since he spends a lot of time floating around in a boat, and apparently not a lot of time winding in fish.

quote:

Hey, if you are getting consistant readings then you are doing very well indeed. The Hornady (Stoney Point) OAL Gauge takes some practice and not all of us are capable of leaning to use the "thingy", right H C?

Hmmm....Kind of like programing the VCR, eh?

Hey Ol` Joe, Fine looking youngster. Nice "toy" to occupy some of his time.

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Originally posted by Hot Core:
Hey Ol` Joe, Fine looking youngster. Nice "toy" to occupy some of his time.

Youngster hell, that's Ol'Joe himself.

It just might be.

Hey Ol` Joe, Just looking at the flick a bit closer and noticed the cant of the Bullet entering the Thingy. How do you control the cant(skew, wobble, mis-alignment, whatever) so a person gets a "consistent reading"? (Didn't want to say "accurate reading", since we all know better. )

It's something in the water here, that keeps us looking so young

Look closer and you'll notice that the case head isn't touching the other jaw (yet). Like any other length measurment with a caliper you need to make sure that the case head is flat and centered aganst the other jaw.

Of course some of us have .0001 indicators, granite surface plates, Starrett height gauges that read to .0001 etc etc and only resort to using calipers for rough (+/-.002) measurments

quote:

Originally posted by Hot Core:
It just might be.

Hey Ol` Joe, Just looking at the flick a bit closer and noticed the cant of the Bullet entering the Thingy. How do you control the cant(skew, wobble, mis-alignment, whatever) so a person gets a "consistent reading"? (Didn't want to say "accurate reading", since we all know better. )

Wish I was that young again...

Tailgunner is right the cartridge is just being set into the gage and the caliper is open wide. He sets the bullet in the gage closes the jaw and wiggles the cartridge as he does it a bit. He closes the jaws a bit tight but he is learning. This "seats" the cartridge in the jaws and measurments seem to come out real close/consistant cfor him. The little guy loves helping Grampa. He actually can measure pretty well for a 4 yr old. (the pic is old he`s 7 now) He seems to hold the tolerance to +/-~0.002" or so and although he doesn`t get the "scale reading" right he will tell me it measures "35 and 2 lines" or what ever on the dial.

Hey Tailgunner, are you open for a cup of coffee the 13th or 14th this year? I`m planning on heading up the 13th at the moment. The doe permit came in the mail today and a license in hand always starts getting me antsy.

quote:

Originally posted by Ol` Joe:
... He actually can measure pretty well for a 4 yr old. (the pic is old he`s 7 now) He seems to hold the tolerance to +/-~0.002" or so and although he doesn`t get the "scale reading" right he will tell me it measures "35 and 2 lines" or what ever on the dial....

Good for him. You've taught him well.

That is waaaaaay better accuracy than denton and his band of dip sticks could measure CHE & PRE.

quote:

Originally posted by Ol` Joe:
Hey Tailgunner, are you open for a cup of coffee the 13th or 14th this year? I`m planning on heading up the 13th at the moment. The doe permit came in the mail today and a license in hand always starts getting me antsy.

The 14th would work, I'll probably work Monday and Tuesday that week, and take the entire next week of.