I have the first gen MPA chassis (see pic) and dropped a MTU barrel in there. I was able to fit two pieces of paper in between the top (NV mount) and bottom channel area but when I went to three, it got clogged. I loaded some rounds for load development (see pic) and got some good groups at the lower charge range but the groups expanded quite a bit at the higher charge range (up to 43gr) I plan to continue working up the load because I had zero pressure signs at the highest charge. However, I wonder if the poor grouping at the higher charge is because the barrel may be contacting the chassis?? I do not want to do any smithing work so am thinking:
1. Pull off the NV mount
2. Pull off the NV mount and fit a hard plastic between the lower barrel channel and the barrel; I would use the same type of plastic I use between my barrel and barrel block when I bolt down my unlimited barrel into my barrel block on my rail gun.
3. Leave it all and put plastic between the barrel and channel.
4. Do nothing and see how the higher charge loads do.
Any ideas, advice, etc. is appreciated.
1. Pull off the NV mount
2. Pull off the NV mount and fit a hard plastic between the lower barrel channel and the barrel; I would use the same type of plastic I use between my barrel and barrel block when I bolt down my unlimited barrel into my barrel block on my rail gun.
3. Leave it all and put plastic between the barrel and channel.
4. Do nothing and see how the higher charge loads do.
Any ideas, advice, etc. is appreciated.