I shot my V53 this weekend both suppressed and without suppressor.
While doing some cleaning I noticed some roller marks on the receiver. I guess I need a different locking piece while suppressed?
How bad is this and do I need to worry about shooting it now?

Check put the Henderson HK high round count post,  He mentions something about this possibly being caused by  weak recoil springs.

Is your carrier buffered?

If I'm not mistaken Henderson was describing the carrier hitting the end end cap/ stock and casing damage to receiver. The damage to mine is just behind the chamber which is further forward on receiver at beginning of bolt travel.


Yes to the buffered carrier.

Whether the carrier is buffered or not has nothing to do with bumps in this particular location.

These bumps are caused when the bolt hits the top round in the mag.

IMO they are not a big deal.

Can you elaborate? I have never seen nor heard of this problem, and seems to me from my basic understanding- if the rounds are causing enough resistance for the rollers to pop out and dent the receiver in that way, rounds are not feeding correctly? Back to the "Running" vs "Running Right" argument I suppose...

If you are saying that when the bolt travels forward to strip the top round out of magazine the the rollers can cause the bumps. That would put the bolt at it's rear most position not in a position to cause the roller marks that I have?

Roller dents in the front of the receiver are usually pretty rare.

The classic roller dent issue is usually in the rear of the receiver.  This is caused when the recoil force is too excessive due to either a worn recoil spring, incorrect/worn locking piece, worn locking lever, hot ammo, suppressor use, incorrect bolt gap or some combination of some of all of these symptoms.

Basically the net is that the bolt carrier comes back with too much force and when it bottoms out on the stock the bolt "head" continues to travel backward pushing the rollers back against the locking piece (extending them outwards) and denting the rails in the receiver.

However, in your case the rollers dents appear to be in the front section of the receiver just aft of the trunion.   The only reason this is happening is because something is causing friction on the bolt head during the return stroke to battery.  This friction on the bolt head cause the carrier to push the locking piece against the rollers forcing them out from the bolt head prematurely before the bolt head is fully seated into the trunnion.

This can be caused by a couple of issues.

1. If you have recently had a number of malfunctions that end up with "stovepipe" type of jams the bolt & carrier slams home on a case stuck in the action, forcing the rollers out prematurely.  (however these dents are usually along the rails a bit farther back than yours)

2. If the magazine is too high it can can catch the bottom of the carrier.  (however based on your roll mark locations I think they are way to far forward for the mag to be causing this as the dents would be behind the ejection port where the bolt head first makes contact with the rear of the mag.  Where your marks are the round is already fully stripped from the mag)

3. The trunnion is slightly out of alignment and the bolt carrier is clipping/dragging on the trunnion during the closing cycle, slightly forcing the rollers outward into the receiver.  

4. Its also possible that the carrier cocking tube is hitting the cocking tube weld on the receiver.  These Vector 53 use modified HK33 which the cocking tube cut back and profiled.  Its possible that the carrier is not relieved enough and is encountering resistance when entering the cocking tube portion of the receiver.


Based on where the marks are (slightly aft of the trunnion) it looks to me like the front edge of the bolt head is encountering some type of resistance when transitioning from the sheet metal receiver into the steel trunnion or the cocking tube on the carrier is encountering resistance going into the cocking tube which is welded to the receiver.

I would run the bolt carrier back and forth in the receiver by hand and see if it encounters any significant resistance.  While doing this I would also try to twist the carrier up/down/left/right to see if there is a specific angle you can feel it hang up where the roller marks are. You may need to grab some threaded rod and a couple bolts from home depot to run through the cocking tube on the carrier so you can freely actuate the carrier manually up and down the receiver.  Alternatively you could remove the pistol grip and try and manipulate it with your fingers.

I would also inspect the trunnion and bolt head for any shiny spots that may indicate wear where resistance is being encountered.

I wouldn't continue to shoot it as the dents will only get worse if the problem still exists.  

As the dents get larger enough they will continue to expand until the point that they are able to fully  "catch" the rollers and hang up the carrier completely during the return stroke, which then just dramatically accelerates the dents and makes the receiver unserviceable.

Edited to add, looking at your picture again but is the edge of the steel trunnion raised above the sheet metal receiver?  the trunnion should be flush with no raised lip.  You should be able slid your finger down the inside of the rail and the transition from the sheet metal to the trunnion should be completely smooth.

Attached File

Looks like the trunion on is really close to flush but there is a very small ridge. The trunion sticks out past receiver just a tad.
This is mine


This is a friend's