Bullet not seating completely

Could have any number of causes. You don't mention bullet manufacturer or the cartridge overall length? Are you loading to the bullet manufacturer's specifications? I see a barrel and cartridge protruding but I have no numbers? I assume a squeaky claen chamber? Properly sized case? Have you taken any measurements?

Ron

More taper crimp and/or shorter OAL may fix it.

And the [loaded] case mouth diameter is.... ?



Measure it and tell us what it is.....

Any time there is a "fit" problem, measure! Plus the plunk test is just a static test; go/no go. It will tell you if the cartridge (a bullet is a part of a cartridge) fits the chamber and you need to find out why...

Bullet profile; bullets may be hitting the lands. Not enough "crimp" (still some flare in the case mouth. Over crimping can bulge the case. Just three reasons a cartridge won't chamber...

1.275 is Maxium OAL not Minimum

A 185 SWC will never seat to the MAX length of 1.275" without the front driving band jamming into the rifling leade.

You seat any weight SWC so just about a thumbnails thickness of the full diameter front driving band is outside the case mouth.

If in doubt, color a loaded round with a black magic marker and force it into the chamber all the way.

Where the ink rubs off is how much shorter you need to seat it to clear the rifling leade.

Then?
Whatever the OAL measures, is the correct OAL for that bullet design.

But, it will be with most of the front driving band on the bullet, Inside the case.

rc

If you read the first page for the 45ACP, It clearly states that 1.275 is MAX OAL

Your Speer manual probably says 'Max Cartridge Length 1.175"'.

That means exactly what it says.

But bullet shape determines what will fit in your chamber without the bullet ogive striking the rifling leade before the cartridge is fully chambered.

If you further notice, each bullet weight and shape has a different OAL as tested.

It is true the Speer 185 Total Metal Jacket is shown as 1.275".

But it has an exceptionally Long nose shape for a 185.

You might notice the lead 200 SWC next to it is shorter for weight, and was tested at 1.185".

The 185 Gold-Dot is shorter still and was tested at 1.200".

So unless you are using Speer bullets, don't rely on Speer, or any other reloading manual OAL.

Use your guns barrel as the gage, and determine it yourself by what will fit in it, and what won't.
(With the bullet shape you are using.)

"You seat any weight SWC so just about a thumbnails thickness of the full diameter front driving band is outside the case mouth." rcmodel

Here is a picture of what rcmodel is suggesting

Then as the [other] folks have suggested, get the OAL down to just a bit of shoulder showing.