Bushmaster Questions

[Toestr]

A couple questions about the Line SI Bushmaster.

1. Do the safeties on these just not work? Mine will just slide into the fire position if the trigger is pulled on safe. I tried increasing the tension for the detent and also punching notches into the frame for it but still nothing. I think the part of the slider that catches the trigger is too short.

2. Are the valve thumbscrews necessary? I'd rather just leave them out instead of having to deal with loctiting or checking on them all the time.

[Grendel]

1. With stock spec parts they work fine. Sounds like you have modified or out of spec parts.
2. Will they work without the extra thumb screws, yes. They do make it easier to reassemble the marker if you have a Bushmaster that still has them, you must have a body from pre-1990 later bodies did away with this structure.

[Toestr]

Thanks. I meant the small thumbscrews that come off the valve at a 45. Can I just leave those holes empty or does there need to be something there for stability of the valve?

[Grendel]

Yup, not really needed, Unless you have one of the Nelson upgrade bodies they need those small screws to hold stuff together. If you have the Big bolt that goes all the way through the valve body into the frame you do not need the two little bolts.

[Painthappy]

As long as you have the main single bolt going through the entire valve, the valve should be fine, but on the ones that were held in by a small screw under, the top two smaller screws in the valve will be needed. Just too much pressure on the one single bolt (if it doesn't go all the way through). The hammer is slamming back on that so you want extra support.

[Toestr]

Thanks guys.

I've been trying to get this up to speed with 12gs and it's maxing out in the low 200s (#6 SI powertube, heaviest hammer spring, lightest valve spring). I also tried it with a #0 SI powertube and it's about the same maybe a little less. 20-25°C days. The only other thing I can think of to do is devolumize the valve the bit I can. A smaller bore barrel isn't really an option (I know about Doc's Freak backs but I'd imagine those are difficult to find popping up).

Any other suggestions?

[The Inflicted]

Thanks guys.

I've been trying to get this up to speed with 12gs and it's maxing out in the low 200s (#6 SI powertube, heaviest hammer spring, lightest valve spring). I also tried it with a #0 SI powertube and it's about the same maybe a little less. 20-25°C days. The only other thing I can think of to do is devolumize the valve the bit I can. A smaller bore barrel isn't really an option (I know about Doc's Freak backs but I'd imagine those are difficult to find popping up).

Any other suggestions?

I also had problems getting my Bushmaster up to speed and-respringing only did so much. What worked for me was:

1.) Going to a heavier hammer. Mine came with an aluminum hammer which I assume is factory but was very lightweight. I swapped in a heavier generic Nelson hammer from Bacci.

2.) Changing out the cupseal. Not sure if the one in my valve was factory or not but it was very wide to the point that I think it was restricting the flow around it when open. I used a normal 'cocker-sized cupseal on the valve stem and it improved things.

3.) Freak-boring the barrel. Expensive but necessary, as this also solved my rollout problems.

[Toestr]

Hmm I never thought of the hammer. Much lighter than my SL68 hammer. Unfortunately velocity adjustment is done at the hammer instead of the bolt. I suppose I could drill and tap a steel hammer for adjustment, but I also don't want to lose the awesome trigger break the stock sear gives.

I think a Doc's Freak back will be the way to go. I've been using a detent ring and it's stopped double feeds and rollouts but I still get huge blowby. I might also see about getting an oring slot in the bolt.