Hw30 / R7 lock up issues and fixes
I've read about people having vertical stringing and lock up issues with Hw30s. Sometime ago I wrote up a post explaining what I found when I was trying to fix a sinking POI when shooting for extended sessions. What fixed that rifle was thinning the breech seal only a few thousandths of an inch. I applied the same fix to my next Hw30 when new and all was good until recently. After several thousand rounds the cross pin the ball locks against was worn. Pushing out the pin and rotating it to move the worn spot restored the lock up.
Many people here know how enamored I am with the Hw30 / R7 platform. In an effort to champion the rifle and hopes of helping others get the same amount of pleasure out of them as I do, I compiled my experiences and made this post.
First the most common lock up issue with the Hw30 is the pivot bolt tension being too tight. A good indication of this is if you have vertical stringing in your groups. They generally come too tight which can leave the rifle locked up at various places, especially if the breech seal is slightly too thick. I’ll address that later. They are delivered on the tight side because they generally loosen as they wear.
The fix is usually to adjust the barrel pivot bolt so there’s just enough tension to hold the barrel outward at a right angle to the compression tube after the rifles cocked. Too loose you'll have problems too, but that usually causes random loose grouping. Sometimes new guns have stiff cocking linkages that will hold the barrel out when the pivot is still loose. Typically I like the barrel just tight enough to remove the side play. If the barrel drops or hangs it still should be good.
Second common issue is the breech seal is slightly too thick. This holds the breech block off the cross pin its supposed to lock against. Without this solid metal to metal contact the flexible dimensions of an elastic breech seal vaguely determines the final lock up position. On the Hw30 good lock up requires the step milled into the breech block be held against the 4mm cross pin in compression tube (receiver). You can see this pin with the gun cocked and open. It's below the transfer port.
You can tell if your Hw30 is locking up correctly if it feels solid and sort of clacks when you latch the barrel. If it sounds muffled and feels soft it’s probably resting on the breech seal rather than the cross pin as designed. A second way is to see if there’s a witness mark in the step where the pin makes contact. A new gun may not show a witness mark for sometime. In this case, spread a very thin layer of white grease or krytox on the step and latch barrel and see if it the cross pin prints in the grease.
Before I suggest a repair I want to inform you that all OE Weihrauch breech seals are slightly too thick when new. By slightly too thick, I mean by .006”. That’s only the thickness of two loose leaf sheets. It’s not a lot but it makes a difference. That small difference will move the POI 1/4"+ at only 10 yards. It's 3 times that much at 30 yards. I believe the seals are deliberately made on thick side because they flatten with use. Providing your pivot bolt is adjusted correctly, there's a good chance any vertical stringing your having with your new Hw30 will cure itself as the seal flattens with use. Sometimes wiping a very light smear of silicone grease on the breech seal where it contacts the compression tube will help it settle close to the same spot. This sometime helps get a more repeatable lock up until the seal flattens to the correct thickness.
If your an impatient perfectionist like me you can thin the seal. I did this by stretching it on a dowel end, chucking the dowel in a drill and sanding the thickness down with 100 grit. The white Weihrauch seals start off around .177”-.178” and sanding them down to .171”-.172” seems to be the ticket. Too much off and you’ll leak pressure.
I have tried aftermarket seals with varied luck. I found the Black Vortek breech seals thicker and harder than the Weihrauch so they're not a good choice for this rifle. I have also tried the green Marcarri breech seals with good results. While initially thicker than OE white seals they are softer and for the lack of a better term they smoosh better to size than the Weihrauch. I used to recommend them as they do initially work well but they tend to get gummy and deteriorate quicker than the Weihrauch. I've been staying with the OE seal lately.
Whenever installing or reinstalling a breech seal put it in dry and in from one side first. This prevents air, oil or grease from getting trapped under the seal which would cause it to not fully seat, creating more problems. Some companies make radial grooves around the seal's perimeter to prevent this. Because it’s natural to want to lube a new seal, some guns are fixed by simply removing the seal drying the seal and groove and reinstalling it.
The third and final lock up issue I've encountered with these guns is the receivers 4mm cross pin wears where the detent ball contacts it. This effectively makes the cross pin undersized. Eventually the ball detent can't extend far enough to lock the breech to the cross pin. When this happens very slight but well defined play can be felt with the barrel latched. Similar play can be felt with the thick breech seal issue but the difference is the way it sounds and feels. I had the pin wear on both my Hw30s but only after several thousand rounds. Many people will never shoot theirs that much.
The repair for this one is simple. Knock the 4mm cross pin a little to the side or remove it and rotate 180 degrees and reinstall. This will give the ball detent a fresh full area to lock against. If you wanted to, you could replace the cross pin. It is the same pin as the short trigger cross pin, part number DP095 at Chambers Gunspares in the UK. Replacements can also be had more locally from McMaster-Carr, part number 9595A175. I bought a pack of 25 for a little over 9 bucks. That'll last me several lifetimes.
All in all, none of these things are big deals. Some will rectify themselves with use, some require attention and some only after years of normal use. Honestly, most people aren't as fussy as I am and will never notice the slight variance in accuracy these issues cause. Most are too busy enjoying the gun to notice. If for some reason you're struggling with lock up issues I’ve laid it all out on a plate for you. Oh and by the way the detent ball and spring are not serviceable parts and contrary to internet chat are not really the problem. The problem is understanding the design. You just cant have good lockup without metal to metal contact.
I hope this helps someone enjoy these guns as much as I do.
I've read about people having vertical stringing and lock up issues with Hw30s. Sometime ago I wrote up a post explaining what I found when I was trying to fix a sinking POI when shooting for extended sessions. What fixed that rifle was thinning the breech seal only a few thousandths of an inch. I applied the same fix to my next Hw30 when new and all was good until recently. After several thousand rounds the cross pin the ball locks against was worn. Pushing out the pin and rotating it to move the worn spot restored the lock up.
Many people here know how enamored I am with the Hw30 / R7 platform. In an effort to champion the rifle and hopes of helping others get the same amount of pleasure out of them as I do, I compiled my experiences and made this post.
First the most common lock up issue with the Hw30 is the pivot bolt tension being too tight. A good indication of this is if you have vertical stringing in your groups. They generally come too tight which can leave the rifle locked up at various places, especially if the breech seal is slightly too thick. I’ll address that later. They are delivered on the tight side because they generally loosen as they wear.
The fix is usually to adjust the barrel pivot bolt so there’s just enough tension to hold the barrel outward at a right angle to the compression tube after the rifles cocked. Too loose you'll have problems too, but that usually causes random loose grouping. Sometimes new guns have stiff cocking linkages that will hold the barrel out when the pivot is still loose. Typically I like the barrel just tight enough to remove the side play. If the barrel drops or hangs it still should be good.
Second common issue is the breech seal is slightly too thick. This holds the breech block off the cross pin its supposed to lock against. Without this solid metal to metal contact the flexible dimensions of an elastic breech seal vaguely determines the final lock up position. On the Hw30 good lock up requires the step milled into the breech block be held against the 4mm cross pin in compression tube (receiver). You can see this pin with the gun cocked and open. It's below the transfer port.
You can tell if your Hw30 is locking up correctly if it feels solid and sort of clacks when you latch the barrel. If it sounds muffled and feels soft it’s probably resting on the breech seal rather than the cross pin as designed. A second way is to see if there’s a witness mark in the step where the pin makes contact. A new gun may not show a witness mark for sometime. In this case, spread a very thin layer of white grease or krytox on the step and latch barrel and see if it the cross pin prints in the grease.
Before I suggest a repair I want to inform you that all OE Weihrauch breech seals are slightly too thick when new. By slightly too thick, I mean by .006”. That’s only the thickness of two loose leaf sheets. It’s not a lot but it makes a difference. That small difference will move the POI 1/4"+ at only 10 yards. It's 3 times that much at 30 yards. I believe the seals are deliberately made on thick side because they flatten with use. Providing your pivot bolt is adjusted correctly, there's a good chance any vertical stringing your having with your new Hw30 will cure itself as the seal flattens with use. Sometimes wiping a very light smear of silicone grease on the breech seal where it contacts the compression tube will help it settle close to the same spot. This sometime helps get a more repeatable lock up until the seal flattens to the correct thickness.
If your an impatient perfectionist like me you can thin the seal. I did this by stretching it on a dowel end, chucking the dowel in a drill and sanding the thickness down with 100 grit. The white Weihrauch seals start off around .177”-.178” and sanding them down to .171”-.172” seems to be the ticket. Too much off and you’ll leak pressure.
I have tried aftermarket seals with varied luck. I found the Black Vortek breech seals thicker and harder than the Weihrauch so they're not a good choice for this rifle. I have also tried the green Marcarri breech seals with good results. While initially thicker than OE white seals they are softer and for the lack of a better term they smoosh better to size than the Weihrauch. I used to recommend them as they do initially work well but they tend to get gummy and deteriorate quicker than the Weihrauch. I've been staying with the OE seal lately.
Whenever installing or reinstalling a breech seal put it in dry and in from one side first. This prevents air, oil or grease from getting trapped under the seal which would cause it to not fully seat, creating more problems. Some companies make radial grooves around the seal's perimeter to prevent this. Because it’s natural to want to lube a new seal, some guns are fixed by simply removing the seal drying the seal and groove and reinstalling it.
The third and final lock up issue I've encountered with these guns is the receivers 4mm cross pin wears where the detent ball contacts it. This effectively makes the cross pin undersized. Eventually the ball detent can't extend far enough to lock the breech to the cross pin. When this happens very slight but well defined play can be felt with the barrel latched. Similar play can be felt with the thick breech seal issue but the difference is the way it sounds and feels. I had the pin wear on both my Hw30s but only after several thousand rounds. Many people will never shoot theirs that much.
The repair for this one is simple. Knock the 4mm cross pin a little to the side or remove it and rotate 180 degrees and reinstall. This will give the ball detent a fresh full area to lock against. If you wanted to, you could replace the cross pin. It is the same pin as the short trigger cross pin, part number DP095 at Chambers Gunspares in the UK. Replacements can also be had more locally from McMaster-Carr, part number 9595A175. I bought a pack of 25 for a little over 9 bucks. That'll last me several lifetimes.
All in all, none of these things are big deals. Some will rectify themselves with use, some require attention and some only after years of normal use. Honestly, most people aren't as fussy as I am and will never notice the slight variance in accuracy these issues cause. Most are too busy enjoying the gun to notice. If for some reason you're struggling with lock up issues I’ve laid it all out on a plate for you. Oh and by the way the detent ball and spring are not serviceable parts and contrary to internet chat are not really the problem. The problem is understanding the design. You just cant have good lockup without metal to metal contact.
I hope this helps someone enjoy these guns as much as I do.
