Timing help

[Pwoller]

I have a Lilja 12.5 barrel and headspaced maxim bolt. I shoot suppressed with this gun and I get ejector marks on all brass factory and hand loads. I’ve beveled the ejector went up in spring and buffer weight and I’m still getting the ejector marks. The only time I don’t get them is if I shut the gas all the way off. So that is pointing to early unlocking. What are my options to get this corrected? Anyone run a similar setup and had luck fixing this? I’m to the point I’m considering running factory loads and just pitching the brass. Very frustrating.

[grendelnubi]

Have you checked to see where your brass is ejecting to try and determine if you are over-gassed or not? I also was getting the ejector mark and cleaned my bolt and they seem to have went away. Check to see if your ejector spring is working freely. The plunger should travel below the bolt face.

[VASCAR2]

Some people clip coils off the ejector spring to keep from getting the swipe which is very common on a lot my 6.5 Grendel brass. As long as my velocities are within normal range, the brass ejects around 3-4 O clock and primers aren’t flattened I don’t worry about ejector swipe.

[Pwoller]

I tried clipping a couple coils off the ejector spring but problem didn’t go away or get better. I just checked and I have an h3 buffer in there and the spring looks like a standard spring. I noticed this after I ordered a jp silent buffer, I got the one with different strength springs so I could play around and see if I can clear it up. With the h3 and regular spring I wonder if I’m actually over gassed to get it to cycle.

[VASCAR2]

Using a suppressor it is very common to be over gassed. I assume your not using an adjustable gas block, adjustable carrier key or adjustable gas bolt carrier. An adjustable gas system might be an easier fix if your using a fixed gas system.

[Pwoller]

I have an adjustable gas block. I typically reload 100 grain bullets or less and had switched to a h3 buffer with those. I’m thinking I was over gassed trying to get the heavy buffer to lock back with the 123s maybe causing the swipes. I’m hoping with the jp buffer and springs I can retune the gas block and clear some of the swipes up.

Here are my chrono results with the gas block closed.
Arcomp:
25.6-2120fps
25.8-2145fps
26-2167fps
26.2-2185fps
26.4-2200fps
26.6-2220fps
26.8-2229fps
27-2255fps
27.2-2262fps
27.4-2275fps
27.6-2276fps
27.8-2299fps
28-2314fps

8208xbr
26.7-2107fps
26.9-2174fps
27.1-2181fps
27.3-2198fps
27.5-2207fps
27.7-2256fps
27.9-2276fps
28.1-2273fps
28.3-2317fps
28.5-2315fps

Hornady brass cci 450 primers 2.25 oal .020 off the lands.

[VASCAR2]

I never tried any buffers/springs heavier than supplied with an adjustable gas block. I just adjusted the gas to where it would cycle the weakest ammo I shot which usually was Wolf steel cased 100 grain fmj. I’ve never run a suppressor because their illegal in Illinois. My thoughts are you should be able to adjust the gas to function with about any buffer or spring unless there is insufficient gas to cycle the action even if the gas block is completely open. If there is insufficient gas then usually you need a larger gas port but your gas port appears to be permitting sufficient gas.

I have no idea if you can adjust the gas to reliably run with and without the suppressor without changing the gas setting.

I think your reloads are not overly hot but each powder bullet combination have their own unique pressure curve. I noticed on my over gassed 16” 6.5 Grendel with carbine gas system there was a significant difference in how the rifle functioned in regards to powder and bullet used. A lighter bullet wouldn’t cause the bolt to unlock to early like the heavier bullets with the same powder. Since my 16” barrel had a huge gas port I fixed it with an adjustable carrier key. I set it to lock open on Wolf and it now functions properly with any ammo I’ve tried. With a 12.5” barrel and throwing a suppressor onto the barrel might mean you will need to adjust the gas for different ammo.

If the only time your getting ejector swipes is on your heaviest charge with 100 or 123 grain bullets then you’ll either have to adjust the gas or reduce your powder charge to eliminate the swipe. I have never noticed an ejector swipe shorten the life of my reloading brass in the 6.5 Grendel. I see the ejector swipe in the same way I view the dent in the side of the brass case, normal occurrence with a gas operated semi auto.

[Pwoller]

I never tried any buffers/springs heavier than supplied with an adjustable gas block. I just adjusted the gas to where it would cycle the weakest ammo I shot which usually was Wolf steel cased 100 grain fmj. I’ve never run a suppressor because their illegal in Illinois. My thoughts are you should be able to adjust the gas to function with about any buffer or spring unless there is insufficient gas to cycle the action even if the gas block is completely open. If there is insufficient gas then usually you need a larger gas port but your gas port appears to be permitting sufficient gas.

I have no idea if you can adjust the gas to reliably run with and without the suppressor without changing the gas setting.

I think your reloads are not overly hot but each powder bullet combination have their own unique pressure curve. I noticed on my over gassed 16” 6.5 Grendel with carbine gas system there was a significant difference in how the rifle functioned in regards to powder and bullet used. A lighter bullet wouldn’t cause the bolt to unlock to early like the heavier bullets with the same powder. Since my 16” barrel had a huge gas port I fixed it with an adjustable carrier key. I set it to lock open on Wolf and it now functions properly with any ammo I’ve tried. With a 12.5” barrel and throwing a suppressor onto the barrel might mean you will need to adjust the gas for different ammo.

If the only time your getting ejector swipes is on your heaviest charge with 100 or 123 grain bullets then you’ll either have to adjust the gas or reduce your powder charge to eliminate the swipe. I have never noticed an ejector swipe shorten the life of my reloading brass in the 6.5 Grendel. I see the ejector swipe in the same way I view the dent in the side of the brass case, normal occurrence with a gas operated semi auto.

Ok thanks for the help.