Note - What follows is neither scientific nor performed by anyone with great ability or knowledge. It is one boys odyssey to find out what works better for him. This may be interesting to some of you.
I took my #10 sighted 03A1 to the range with 200 rounds of KA 73 ammo to test whether I had better target results with a repro set of #10 sights or the narrow blade small aperature standard Springfield sights. I had a theory that the USMC sights were excellent for combat applications but that the narrow sights would be better suited to range use.
I first took ten shots cold bore with HXP 78 to foul and heat the bore. These ten shots were fired with the USMC sights.
Than I used a standard 100 yard target modified to include 4 additional bulls so I could fire four sight groups of five followed by thirty at the center bull.
This was the target fired on with the USMC sights.
Than I changed the sights to a WWI base/leaf and a narrow blade front to fire a similar series of shots.
This was the target fired using the Standard 03 sights.
I think there was marked improvement with the standard sights even despite the fact that the WWI sight was loose with about a unit of windage play left/right and it rocked fore and aft on its base. I than fired 50 (45 shots offhand) at a mansize target and than 50 (off the bench) at a 100 yard target.
USMC sight picture
Standard sight picture
I used the two sights to the left. The new Perry Point sight would not fit the barrel base.
This is the rifle
Until I have to use this 1903 in battle I will stick with the standard sights. I didnt want to make any changes to the barrel base to tighten up the WWI sight so I took the #10 plate out of the original base and replaced it with one marked 4 but apparently reamed out larger (+5). Many of the parts to experiment with this rifle were provided on this and the CMP site, thank you all for your help.