Sorry, not possible. Breach face won't be the correct size, Magazine and mag well, frame would need to be longer for the cartridge size. I am sure there are more reasons I don't know about. Maybe someone with a SW99 in .45 could help out with the differences (if they make one?).
According to what I read here it looks like there may be a couple of vendors looking into this....could be the 45GAP round could be more of a fit than a ACP as I would agree the fit could be problematic...
You can buy an aftermarket .357 sig barrel that will work in your .40 P99, but you can't just buy a .45 barrel and have it work. The numbers just don't add up.
See banddr2's post above.
I like the 45 GAP idea, but Walther would have to buy into it to make a slide that would work. I would buy one, Law Enforcement would need to use the 45 GAP before Walther would get into it.
Case Type
Max. Case Length
Case Size Comparison
Max. Cartridge Length
Bullet Diameter
.45 ACP
0.898”/22.81mm
0.138”/3.51mm longer than the .45 GAP
1.275”/32.39mm
11.5mm
.40 S&W
0.850”/21.59mm
0.09”/2.29mm longer than the .45 GAP
1.135”/28.83mm
10mm
.45 GAP
0.760”/19.30mm
0.138”/3.51mm shorter than the .45 ACP
1.137”/28.88mm
11.5mm
9 mm
0.754”/19.15mm
0.006”/0.15mm shorter than the .45 GAP
1.168”/29.67mm
9mm
"Calling the 45GAP a “short .45ACP” is a misnomer since the ACP and GAP cases are quite different, both inside and outside. The GAP has an entirely new design. Unlike the .45ACP, the .45GAP case rim is slightly rebated (smaller diameter) so the case can be easily extracted/ejected in a 9mm size pistol. The mild rebated rim adds reliability for using the fat 45 case in a .40 sized pistol frame."
Interesting, I like the idea of the GAP, I just wonder if it would ever catch on like the .40 S&W did. Does anyone know if you loose much velocity compared to the ACP?
They wrote the book on the GAP initially the round was called 45 Glock....then GAP = Glock Auto Pistol once it was recognized by saami.....from what I am reading.
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