How short is too short?

[Mirolynmonbro]

Is there such thing as loading too short? I ran out of blue bullets 147gr fp which I had it load to 1.090 to avoid hitting the lands. I bought a pack of 100 122gr fp from acme bullet and I have to load those at 1.035 to avoid the lands.

Does it matter I have to load that round short as long as it feeds reliably?

I think the acme's are a larger diameter than the blue bullets as well, so I think that contributes to a shorter oal too.

This is with a CZ P07.

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[Peally]

I was just recently involved in a group buy for Acme 124s and I and everyone else I talked to had to load them just as silly short to get them to function. Once I figured that out no issues at all, as long as they feed and you're not experiencing high pressures or excessive FPS you're good to go.

[Mirolynmonbro]

Are you using titegroup? I haven't loaded any yet but I'm curious if I'll have to use less powder with the acmes because of the shortER OAL

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[BehindBlueI's]

I can't speak to your given load, but in general you can get to the point you can cause an over pressure situation if the bullet is set too deep. The gas expands faster than the bullet can escape, the "chamber" is smaller, and thus pressure is much higher.

Some powders can also RADICALLY change burn rates if they are compressed.

So...it depends.

[Mitch]

Titegroup is a fast powder, and shortening overall length has an exponential relationship regarding pressure.

Start low and work your way up slowly. Would probably be a good time to use a chronograph, too.


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[Luke]

GuanoLoco has found that federal small pistol primers are good for detecting pressure signs in minor loads. May try that.

[GuanoLoco]

GuanoLoco has found that federal small pistol primers are good for detecting pressure signs in minor loads. May try that.

I also have to load the ACME 124 RNs silly short for my Tanfoglio Stock 2 chambers. The shorter of the 2 requires 1.040". The ACME 135 grain NLG RN's appear to have a more normal nose profile and I can load them at the same length as my Bayou Bullet 135's at 1.095".

Is still too early for me to have a strong opinion on them (124's), but what I don't like is that I would prefer to be able to load everything long for Colt mag PCC reliability and pistols. What I do like it is the price. My current plan is to get the hard chromed Tanfo chambers reamed. CZ barrels can be reamed with more common and cheaper and tool steel reamers.

Pressure definitely rises with shorter OAL, I am definitely seeing more primer flattening with Federals than I do with the 135's. I am not convinced that this is a showstopper though.

[Peally]

I do use Titegroup, and yes you'll need to knock your load down a little as the pressure will rise with the shorter OAL.

The 124s do annoy me as I need to readjust my dies to load them compared to other brands. I'd love to support a company here in WI but I'd be more willing to completely switch to Acme if their bullets were shaped "normally". I don't have direct experience but like Guano mentioned their heavier bullets may be more traditionally designed.

[Peally]

For what little it's worth my current USPSA 124 grain Acme load through a VP9 is:

Powder: Titegroup
Amount: 3.6
Bullet: 124 Acme RN
OAL: 1.080
Power Factor: 131.0432

Compare that to an Xtreme 124 loaded at 1.150 OAL with 4.0g of powder for roughly the same PF.

[Duelist]

I was going to say, no experience with that bullet, but CZ throats can be short.

[Mirolynmonbro]

Titegroup is a fast powder, and shortening overall length has an exponential relationship regarding pressure.

Start low and work your way up slowly. Would probably be a good time to use a chronograph, too.


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I was thinking of starting at 2.8 and going up from there. But I'll have to wait for a local match so I can borrow the club's chrono


I also have to load the ACME 124 RNs silly short for my Tanfoglio Stock 2 chambers. The shorter of the 2 requires 1.040". The ACME 135 grain NLG RN's appear to have a more normal nose profile and I can load them at the same length as my Bayou Bullet 135's at 1.095".

My current plan is to get the hard chromed Tanfo chambers reamed. CZ barrels can be reamed with more common and cheaper and tool steel reamers..

I would just stay with the bluebullets but the grouping isnt all that great and the acme's are a little cheaper. The coating feels stronger as well

Not sure if I can ream the CZ barrel. Some folks on benos say the lining on the P series CZ is too hard


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[Peally]

If it were me personally I'd switch bullet types looooooooong before I modified my gun to work with anything.

[Mirolynmonbro]

If it were me personally I'd switch bullet types looooooooong before I modified my gun to work with anything.
I ordered some blue bullets 135gr TC out of curiosity and was surprised to see I was able to load them up to 1.130 and still pass the plunk test. The profile on these is more pointy compared to the 147 FP and the 122 TC.

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