There is a collection of small arms on display. I'm not much into that sort of thing, so I was pretty sparse with the photos. I did note though that virtually every country's weapons were on display, showing the heterogeneous nature of Poland's armaments in 1919 and 1920 pretty well.
Outside there was an excellent collection of tanks, planes and artillery. I was only interested in the guns used by Poland in 1919-1920, of which there were several.
Weapons in Warsaw a 1.0 MB .zip file if you want all of them.
There were many weapons scattered around as well between the uniforms, especially machine-guns and mortars. The rifles were mostly attached with appropriate mannequins, and I have noted some, but not all, of them on the uniform pages.
Lewis gun. Plenty of these saw service, especially by the Whites.
Chauchat MG. Less common, but they were used.
The French Dumesille mortars, and their (enormous) bombs.
Russian mortar. I think it is a 9cm Type GR. This photo makes it look a bit too squat.
Austrian mortar. I think it is a 9cm M14/16.
The MG of the Russian Civil War, a Maxim in the wheeled variant.
Also interspersed among the mannequins were saddles.
English saddle. Added to complete the set of saddles likely to be worn by the Poles (although this one was actually in Krakow).
At the time I was looking for appropriate models to represent my horse artillery (without luck) and heavy artillery, so I took rather more photos of artillery than I usually would.
An obsolete 75mm Schneider M1897, pressed into service by the desperate Poles.
M1904 76.2mm Mountain Gun made by the Obuchovsky Factory in Russia. They could be broken into 5 pieces for transport by mule. While only a few hundred were built, they were liked by RCW horse artillery because they were so light. Other angles are in the zip file.
The M1909 76.2mm Mountain Gun built by Schneider in France, and then from 1909 in Russia. This particular gun was produced in 1915 at the Putilov Factory in St Petersburg. Designed to be broken into 6 main components for transport by mules. By 1914 the Russian Army had 440 of them and many were made during the war. Other angles are in the zip file.
M1902/30 76.2mm Field Gun, based on the Putilov M1902 gun, of which there were 7,621 by June 1917. This is a 1930 variant, but the original was the standard artillery of the RCW (and the fact the Poles and Russians kept using it, suggests a good design). Another angle is in the zip file.
BL Mk1 60-pdr Field Gun (127mm), built in Great Britain, and 52 delivered to Russia. This gun was used by the Red Army and captured by the Poles on the Northern Front in 1920. Another angle is in the zip file.
M1910/30 122mm Field Howitzer. The original model was designed by Schneider in France, but 558 were produced in the Obuchovsky Factory in Russia up to 1917. Production continued by the Red Army.
M1917 155mm Field Howitzer. Built by the Schneider company in France, a number were delivered to Poland in mid-1919 and were used at the Battle of Warsaw. There were 206 in the Polish Armed forces in October 1920.