From everything I have learned about the MAS 49/56 it is best to stick with the civilian version of French ammo at best. I can find it now, and just concern myself with slap fire precautions, even with a modified firing pin. Can't find a titanium one at the moment.

I am not sure if those sooty cases are loads on the low end of the load data, it might help them seal up if you work the charge up slowly until they seal properly. Bill could be right on needing to anneal the necks if they got too work hardened from the brass conversion process. Or the chamber could be loose from excessive wear. Glad you got some to stabilize, when you showed that first target I was worried the bore might be thrashed but looks like it'll shoot fine with the right load.

Definitely a cool rifle. As an aside, aimsurplus does happen to have 7.5 French at the moment for 25/box.

Nice video, and if I may add my reloading experience with the 7.5x54 round in my WW2 MAS 36 and 49/56. This round has a lot of confusion behind it as it relates to max pressures. CIP lists max allowable avg pressure to be 55114 psi, while other standards are listed at 48k, and some at around 40K CUP. I have used data that was published and chronographed from a few decades ago from "Handloader Magazine." They used reformed 30/06 cases but in my experience they are totally unsuitable and potentially dangerous - Just too much space to fill on firing resulting in way over bulged cases, and this was with gallery loads and lead cast bullets I tried to see proof of concept. Your use of 6.5x55 brass could be OK, but many American headstamped 6.5x55 brass uses a std .465"-.470" head diameter (same as 06/.308/.243...) and are not dimensionally correct as is many foreign makers. My Go-To loading is 46.5 grains of IMR 4895, the same M-80 style 147 grain FMJ bullets, Privi cases and CCI-34 primers to prevent slamfires. It performs perfectly, cases look great and it groups tightly and consistently. Avg velocity is 2531 fps from my 49/56. I might also suggest you not use propellants 'slower' than IMR 4064 from your MAS 49/56 - The use of say IMR 4350/similar will have very high gas port pressures when utilized fully, and IMO adds way too much stress to the action and far too violent case extraction. I also use AA2460 and RS TAC with good results in different charge weights too, keeping the velocity north of 2400 fps. In my experience many times you will see that long sooting because the pressure is too low to obturate the case, esp a case that has to expand a lot, and many times you can also see the primer back out too. The use of a higher pressure loading of the correct propellant will also obturate (bump-up) the bullets base diameter which will help with stabilization, especially for these small bearing surface M-80 style 147 gr FMJ-BT bullets. I think once you get your Privi cases loaded up to a more robust loading with IMR 4895 and similar speed propellants you will really like the results.

7.5 French seems to be readily available for a short period of time. Ammoseek has a bunch of listings.

How did the bore look after putting rounds through it? I have an RTI (they refurbed the outside) with a rough barrel. Looked about like yours.

Look to me like the necks need to be annealed, they are allowing gas leakage which tend to mean they are too hard. I will send you an email.

For one you need to search for 7.5 French brass it's out that, that blow by is because your using 7.5 swiss brass that my seem to be the same but there not.

It's semi auto..why did you operate it like a bolt action?