9mm SAAMI question?

[rootacres]

I see that a lot of aftermarket barrels are SAAMI spec, and a few are reamed out for longer loads. What type of OAL should you be able to get with a standard SAAMI barrel? I am currently loading 147 gr rn for minor. Thanks 

[NicoR]

Max OAL as per SAAMI specs is 29.70mm, or 1.1693in.

[Guy Neill]

Much has to do with the shape of the bullet nose. SAAMI allows OAL up to 1.169, as stated above, but some bullets cannot be loaded that long as they will contact the rifling in the barrel.  You need to determine the length the bullet will contact the rifling during initial load development, then shorten the load to a suitable OAL.

 

Look first at any load data from the maker of the bullet, if such is available.  For example, Speer lists an OAL for their loads using their 147gr bullets in the 9mm Luger as 1.130".  This is considerably shorter than the SAAMI allowed maximum OAL, and is very likely due to the bullet contacting the rifling if loaded much longer.

 

It should be some 0.020" off the rifling generally.

 

Guy

[MemphisMechanic]

In a shorter chambered aftermarket barrel, Or a factory gun like a CZ or M&P or XD...

 

Many round nose coated bullets won't load longer than 1.100"

 

The profile is everything. A fat round nosed ACME 124 has to be 1.080" to feed in my M&P. A 125gr truncated cone (TC) black bullets international projectile? Loads perfectly out past 1.150"

 

long pointy bullets vs short fat shoulders  

 

If you're looking to load long, a 147 FMJ or a coated flat-point 147 like Blue Bullets makes? That'll be the easiest bet to load really long.

Edited August 12, 2017 by MemphisMechanic

[noylj]

All barrels sold in the US should be to SAAMI specs unless they are clearly marked differently.

SAAMI can't force the issue, being a voluntary group, but any one NOT doing so opens themselves up to severe liability.

[wgj3]

On 8/11/2017 at 1:59 PM, Guy Neill said:

Much has to do with the shape of the bullet nose. SAAMI allows OAL up to 1.169, as stated above, but some bullets cannot be loaded that long as they will contact the rifling in the barrel.  You need to determine the length the bullet will contact the rifling during initial load development, then shorten the load to a suitable OAL.

 

Look first at any load data from the maker of the bullet, if such is available.  For example, Speer lists an OAL for their loads using their 147gr bullets in the 9mm Luger as 1.130".  This is considerably shorter than the SAAMI allowed maximum OAL, and is very likely due to the bullet contacting the rifling if loaded much longer.

 

It should be some 0.020" off the rifling generally.

 

Guy

Not this "guy's" first rodeo. Worth reading and understanding. Also very good for all the new PCC shooters/reloaders trying to deal with shorter chambers.

[theWacoKid]

17 hours ago, noylj said:

All barrels sold in the US should be to SAAMI specs unless they are clearly marked differently.

SAAMI can't force the issue, being a voluntary group, but any one NOT doing so opens themselves up to severe liability.

 

Knowing OAL for a particular bullet in a "standard" SAAMI barrel isn't going to happen. Basically, the SAAMI specs don't precisely define the throat so there's legitimate variation. The main purpose of the spec is to dimension the chamber and identify headspace.  

Edited August 14, 2017 by theWacoKid

[wrench459]

I've found that I got to measure.

Every manufacturers bullet ogive's are different.

So I'll loose fit a shell -bullet into the chamber.

(Yes, I'm aware that the 9 head spaces  off the shell)

Extract

Then measure the distance for that precise location setup +/-

I will mark the dummy for future reference.

Edited August 14, 2017 by wrench459
oophs..spilling

[MemphisMechanic]

 

It just plain depends on the shape of the bullet, and the chamber on the specific gun you're loading for.

[Wheeljack]

When a manufacturer lists a COL, isn't it just a minimum length based on a RN bullet or the bullet in the specs?

[superdude]

15 hours ago, Wheeljack said:

When a manufacturer lists a COL, isn't it just a minimum length based on a RN bullet or the bullet in the specs?

 

It's simply the length they used for their testing. One can load them longer or shorter if needed/desired. If loading shorter, the pressure usually goes up in handgun cartridges. 

[Wheeljack]

Is it "simply" the length they used?   Thinking of discussions on pressure, I thought the COL listed by a manufacturer was a minimum determined by the pressure, even though the pressure shown was not the SAAMI max.  But then is it just a "safe" length the manufacturer uses that will fit most guns?  If I load shorter, I reduce the power charge and if I load longer, I can increase the powder.  Then I wonder if I should crono these loads to see if the fps remains the same?   I feel we are given figures that are very conservative and vague!  Longer or shorter is important, then why isn't the length of the bullet posted?  Seating depth is more important than COL. The length of a bullet seems to me to be the most variable measure.  The diameter  and weight are pretty consistent but the length less so.  Still when I try loading a new bullet, I compare bullet lengths to determine seating depth and from this the COL.   After doing all this measuring to be safe, some good old boy publishes powder loads 20% over what I use as maximum and loves them.  All in all, the data I read is for SAAMI and not +P or +P+, so if I'm using a new gun and this data, I'm pretty safe.  Isn't this fun? 

[superdude]

 

Don't read too much into it.  It's the length they used for their test. That's all. That length will usually fit most chambers and tends to feed reliably in most semi-auto guns, but it's never a guarantee. It might not fit in your chamber or produce the same pressure in your gun that it did in their test gun/apparatus. I've seen published loads that were safe in one barrel with no pressure signs that were blowing the primers out when fired from another barrel. That's why they recommend that you start below the maximum charge listed and watch for pressure signs if you want to work up to the higher charges. 

 

See the figure that MemphisMechanic posted and the length for the Sierra 125 JHP bullet. Sierra's manual lists that bullet at 1.075" OAL. But that length was too long to fit in the CZ barrel and had to be reduced to 1.036: OAL.  

Edited August 22, 2017 by superdude
add info

[Wheeljack]

I guess if it's easy it won't be any fun.  Thanks

[wrench459]

8 hours ago, Wheeljack said:

Is it "simply" the length they used?   ... Seating depth is more important than COL. The length of a bullet seems to me to be the most variable measure. ..  Isn't this fun? 

I agree up to a point.

Speer 115gr RN boolit length .572 ,Everglades 124 gr JHP  .581, Hornady  xtp 147 gr  .653.

Yep so much fun.