45 GAP in revolver ?

[BobC]

I assume a standard moonclip will allow 45 GAP to be fired in a revolver designed for the 45 acp, e.g., S&W 25 or 625. Has anyone tried this?

Given the GAP's smaller case volume, would there be any efficiency (or other) benefits to using the GAP case for target loads in a 45 acp revolver?

Since discarded 45 GAP brass can now be scarfed up at the local range, I'm just curious whether such brass has potential for my S&W 625.

Thanks in advance,
Bob

 

[Jim Watson]

I would expect it to work about as well as, say, a .40 S&W in a 610.
Since you have the gun and source of brass; why don't you do the shooting and YOU tell US?

 

[Archie]

Like you said...

it has a smaller chamber area. So it might work well for bullseye type target loads.

The other side of the coin is, there is no point in hotrodding it.

And, as brother Watson implied, sounds like you could be the primary researcher and reporter. I'd be interested in the findings. Good luck.

 

[sixgun symphony]

If you want a handgun that shoots .45 GAP, then why not get a Glock?

If you want a revolver, then why not get one chambered in the much more versatile .45 Colt?

 

[Gewehr98]

Sixgun Symphony, perhaps you misunderstand.

The author of the thread was considering shooting .45 GAP in a S&W revolver chambered for .45 ACP. Those revolvers were specifically intended to chamber the autoloading rounds, by way of moon clips. The practice has been around since at least WW1, when we issued our doughboys the S&W M1917, and Colt M1917 revolvers, both chambered in .45 ACP, since the 1911 autoloader was in somewhat of a short supply.

The S&W Model 25 is another revolver that came chambered in .45 ACP, as well as .45 Long Colt. Many Model 25 owners have two cylinders for their guns, and can switch out between the two chamberings.

 

[BobC]

I do not have a range repot, however.....

I have confirmed that 45 GAP will fit in a 45 acp moon clip and will chamber
(and dry fire) in my 45acp revolver.

As far as reloading the 45 GAP though, I am getting cold feet. The only recipe for lead bulets I found was for a 155 LSWC on the Hodgdon site (and I don't have that bullet in my stock). Of the Hodgdon recipes for JHP bullets, the 45 GAP uses less powder (between .6 and 1.0 fewer grains of the same powder) than a 45 acp to get similar velocities with a 200 grain Speer JHP/GDHP, and the GAP has considerably higher pressure (3000 to 4000 more CUP).

Without a chronograph to guide my load development, there are currently too many unknowns for me to tempt the fates to reload the 45 GAP. The fun of reloading a new cartridge will just have to wait for more recipe data to be published.

- Bob

 

[GPappy]

Looks like this thread has been dormant for a while but I would like to add a bit about my investigation and ask a question.

I shortened some .45ACP cases to .45Gap length and had been experimenting with reduced loads to use in IDPA. Yes I know that this may not be in the "spirit" of the competition but they called out a 125K Power Factor for SSR and I was at a disadvantage due to recoil when compared to the .38 super guns firing 9mm and the 10mm guns firing .40 and downloaded at that. Anyway, I had a pretty good load developed for 130K power factor and was going to try that this year. The guys at the range were refering to my brass/loads as 45GRL (Gamer Revolver Loads) or 45 Girl for short.

Now that the rules have changed I need a 165K power factor and I would like to still use the .45gap length brass I made. I want to continue to use this brass because the shorter length really does improve reload times and standard .45Gap brass does not work as well in the .45acp moon clips. Does anyone have a recommendation on how I might go about working up a load for this PF while monitoring pressures? Does the fact that this brass uses LPP make that big a difference or could I use the standard .45gap loads as a safe starting point?

Any help would be appreciated.

Thanks,
Greg

 

[Black Snowman]

Does the fact that this brass uses LPP make that big a difference or could I use the standard .45gap loads as a safe starting point?

Without pressure testing equipment no real way to know. Also keep in mind that GAP is loaded to the equivilent of +P presures anyway.

For the best safety margin I think your best bet is to continue loading in standard .45 ACP cases and simply seat deeper for lighter loads if you have accuracy issues cause by the lighter charges. Maybe load the bullets a little longer in your already shortened brass to get the faster reloads. Just watch for bullet pull.

I'm not an expert, YMMV, and the ususal disclaimers

 

[lbmii]

I am not at all an expert but is not the 45 GAP a much higher pressure round than the 45 ACP? Could this mean that it would be dangerous to fire a 45 gap in a 45 ACP revolver?

 

[GPappy]

Ibmii,

Good question. I am shooting a S&W 625 which is built on a gun that was originally chambered for .44 Mag so I doubt that would be a problem. The 45 Gap length cartridge makes an incredible difference in reload time. Now the fun will be working up a 165K power factor load for the new ESR division. I will be shooting at the S&W IDPA Winter Nationals and hope to be able to get a chance to talk to S&W about getting a cylinder for my gun chambered in .45 GAP.

Greg

 

[larryw]

That's is a great question. The 45 GAP max SAMMI pressure is 22KPSI, which is below the 45ACP +P spec or 23KPSI. So if the revo can handle +P, I'd venture it's OK shooting the GAP.

Scrubbing out the carbon ring in the cylinder bores will be a PITA though (think shooting Special ammo out of a Mag revo).

 

[Mannlicher]

Reminds me of that movie, "Dumb and Dumber"

 

[BluesBear]

If you happen to have some .45gap ammo AND a S&W Model x25 revolver, there is absolutely no reason NOT to fire it in clips. It is NO different than firing .40 S&W in a 610.
Do NOT attempt to fire .45gap in a 1917 Colt or S&W revolver!

Yes the .45gap is loaded a little hotter but it is well within .45ACP+P limits.

As for loading your own.

Simply start with the beginning load for ACP. If your goal is simply target loads then just use target load data. Start at the bottom and work your way up.

I think a target load of Bullseye, Red Dot or Unique behind a 200gr H&G #698 bullet in a .45gap case would be a great load for a revolver.

 

[larryw]

If that's the case, then stick to 45ACP only. A friend has a 610 that went back to Smith THREE times after breaking the firing pin while shooting 40 ammo; its been flawless with 10MM ammo.

So I was thinking about the problem and think I understand why. Both the 10MM and 40SW headspace on the mouth of the cartridge. When you insert a 40 into the moon clip, the forcing cone in the cylinder bore doesn't keep the case from moving forward as it does in the 10. So when the firing pin hits the primer, the case shifts slightly forward, then the ignition bangs it back against the still protruding firing pin, which is when the damage occurs.

 

[BluesBear]

Both the 10MM and 40SW headspace on the mouth of the cartridge.

But when loading in moonclips and fired from a S&W Model 610 revolver they headspace on the clip.

Take a caliper and measure the distance from the front of the cylinder to the base of loaded 10mm cartridges while using a clip. Then load them without the clip and measure again. You will find the distance is a few thousandths shorter without the clip.

 

[larryw]

I understand they space on the clip in the revo. That's what it takes to fire a rimless cartridge in a revo.

How securely does the clip hold the cartridge?

Isn't there a wide variation in the extractor grorove width?

Would this variation explain what my friend has seen as possibly explained by my previous message?

If not, how would you explain this problem?

 

[BluesBear]

Yes there a variance in extractor groove thichness as well as width. But for headspacing purposes the only SAAMI specific dimension is the rim thickness. We are not worried about how high the cartridge can sit in the cylinder because the recoil shield will determine this. We are cincerned with how deep in the cylinder it will sit. That is determined by rim thickness and clip thickness.

SAAMI specifications for 10mm and .40S&W are the same at .050".
In fact the specifications for 10mm & .40 S&W are all the same except for case length and over all cartridge length.

Loaded in a clip .40S&W/10mm have the same relationship to each other as .38 Special/.357 Magnum or .44 Special/.44 Magnum.