Ruger Chambers

[turtlezx]

how about clean and polish the chamber smooooth??
auto loaders are dirty little things

[DougGuy]

From the dimensions of the reamers given, the 2 degree or 1 degree 30min angle on the leade ins is the biggest difference noted in the match chambers as compared to the 5 degree called for in SAAMI 22LR chamber drawings. I wouldn't begin to guess what Ruger puts in theirs. I bet if your chambers were reamed to the 1 degree 30min angle it would stretch out the leade ins far enough that you would get a lot less interference with a live round, and not only would live rounds extract easier, with a gentler leade in I bet they would group better.

[dtknowles]

From the dimensions of the reamers given, the 2 degree or 1 degree 30min angle on the leade ins is the biggest difference noted in the match chambers as compared to the 5 degree called for in SAAMI 22LR chamber drawings. I wouldn't begin to guess what Ruger puts in theirs. I bet if your chambers were reamed to the 1 degree 30min angle it would stretch out the leade ins far enough that you would get a lot less interference with a live round, and not only would live rounds extract easier, with a gentler leade in I bet they would group better.

Look at dimension C those match chambers are much shorter in the body so there is less jump to the leade some ammo might even jam into the leade on chambering. The shortest is Win 52 Match at 0.580" in the middle is Anschutz at 0.619" compared to the way longer 0.775" standard chamber.

The match chambers are tighter on the diameters as well. Basically, the standard chamber is sloppy that is why we have so many different match chambers. People want something better. What is the point of sorting by rim thickness if you are shooting in a sloppy chamber.

Tim

[DougGuy]

Here is the SAAMI drawing of cartridge and chamber. SAAMI lists brass as .613" with chamber length of .643" so that puts the first .030" of driving band in the chamber not the throat, the rest of the driving band is crammed into the rifling leade ins. With a 5 degree throat I can see interference which would explain Ruger's awkward acknowledgement on stuck live rounds.



The Anschutz reamer that you mentioned lists .619" as the chamber body, but it also lists 1/2 degree as the leade angle, so you have this long almost parallel section of throat that all but .006" of the driving bands are carried in when a round is chambered, with less interference than any of the other designs.

I have my own school when it comes to throat length and leade in angles, I won't divulge the exact angle that I have my reamers made on, and I use a considerable amount of freebore before the rifling in reaming centerfire barrels, and it works great. My thoughts run to the "fit the boolit to the throat" side of the equation rather than push the boolit nose into the rifling creating an interference fit upon achieving battery. In other words, I prefer zero interference. Snug fitment of the boolit and the throat (In the case of the 22LR, the throat would have to be fit to the boolit). Let the throat have freebore long enough to serve as an alignment sleeve between the case mouth and the rifling that holds the boolit squared and centered in the bore, then introduce it to the rifling, not cram it into the rifling before it exits the case. I don't get a chance to shoot most of these barrels after they leave my shop, but I can tell you that they don't come back and they don't generate complaints from customers so I assume they are performing well in the field.

I am mildly surprised that none of the reamer designs for 22LR incorporate any freebore. All but the shortest ones like the Anschutz incorporate some freejump, or unsupported freebore. 22LR boolit diameter runs close to .224" and some of the hp run to the large side. S&W kit guns are quite accurate with .2235" cylinder throats, they get a good seal in the throat without too much interference and the boolit exits the front of the cylinder at a diameter larger than groove diameter, so each step of the way the revolver dimensions are reading much like a funnel, getting smaller step by step. This arrangement works very good for any centerfire revolver. I have mentioned the funnel concept numerous times in previous posts on this forum.

So if you look at the longest and gentlest leade angles, and you then look over at the maker, you see a correlation between the high end makers and the longer leade in angles. I would be very inclined to try a reamer designed with a short chamber body such as the Anschutz, but with .100" of parallel freebore .2245" diameter and my own leade in angle which is somewhere among the longer leade in angles but not exact to any of the ones listed.

For the record, the 22 MATCH reamer listed features a very short .600" chamber body, and a very abrupt 5 degree leade in, or the shortest throat. I would suspect the Ruger to be close to this design but I cannot say for sure as I don't own one of these pistols and haven't gotten requests for throat work on them. Generally if there is room for complaint, there is also room for improvement. YMMV...

[dtknowles]

Here is the SAAMI drawing of cartridge and chamber. SAAMI lists brass as .613" with chamber length of .643" so that puts the first .030" of driving band in the chamber not the throat, the rest of the driving band is crammed into the rifling leade ins. With a 5 degree throat I can see interference which would explain Ruger's awkward acknowledgement on stuck live rounds.



The Anschutz reamer that you mentioned lists .619" as the chamber body, but it also lists 1/2 degree as the leade angle, so you have this long almost parallel section of throat that all but .006" of the driving bands are carried in when a round is chambered, with less interference than any of the other designs.

I have my own school when it comes to throat length and leade in angles, I won't divulge the exact angle that I have my reamers made on, and I use a considerable amount of freebore before the rifling in reaming centerfire barrels, and it works great. My thoughts run to the "fit the boolit to the throat" side of the equation rather than push the boolit nose into the rifling creating an interference fit upon achieving battery. In other words, I prefer zero interference. Snug fitment of the boolit and the throat (In the case of the 22LR, the throat would have to be fit to the boolit). Let the throat have freebore long enough to serve as an alignment sleeve between the case mouth and the rifling that holds the boolit squared and centered in the bore, then introduce it to the rifling, not cram it into the rifling before it exits the case. I don't get a chance to shoot most of these barrels after they leave my shop, but I can tell you that they don't come back and they don't generate complaints from customers so I assume they are performing well in the field.

I am mildly surprised that none of the reamer designs for 22LR incorporate any freebore. All but the shortest ones like the Anschutz incorporate some freejump, or unsupported freebore. 22LR boolit diameter runs close to .224" and some of the hp run to the large side. S&W kit guns are quite accurate with .2235" cylinder throats, they get a good seal in the throat without too much interference and the boolit exits the front of the cylinder at a diameter larger than groove diameter, so each step of the way the revolver dimensions are reading much like a funnel, getting smaller step by step. This arrangement works very good for any centerfire revolver. I have mentioned the funnel concept numerous times in previous posts on this forum.

So if you look at the longest and gentlest leade angles, and you then look over at the maker, you see a correlation between the high end makers and the longer leade in angles. I would be very inclined to try a reamer designed with a short chamber body such as the Anschutz, but with .100" of parallel freebore .2245" diameter and my own leade in angle which is somewhere among the longer leade in angles but not exact to any of the ones listed.

For the record, the 22 MATCH reamer listed features a very short .600" chamber body, and a very abrupt 5 degree leade in, or the shortest throat. I would suspect the Ruger to be close to this design but I cannot say for sure as I don't own one of these pistols and haven't gotten requests for throat work on them. Generally if there is room for complaint, there is also room for improvement. YMMV...

How did you establish the length of the bearing surface of the bullet to determine ".006" of the driving bands are carried in when a round is chambered?" It seems SAAMI did not specify what might be the most important dimension, the distance from the base to the leading edge of the first driving band. SAAMI did not give any details of the bullet profile except the diameter of the bearing surface (driving bands). Different nose profiles can also help or hinder proper alignment in the bore. Both my centerfire bench rest rifles have very short leades, so short that the angle must be very steep, way more than 5 degrees. To not jam the bullets into the rifling they must be seated with very little bullet bearing surface outside the case mouth. This is doubly true when shooting 0.310" bullets in a 0.308" barrel. I did not design those chambers I bought the rifles second hand.

Tim

[DougGuy]

I said "all but .006" of the driving bands" if SAAMI spec'd the case at .613" and the Anschutz reamer cuts the chamber at .619" then all of the driving bands are into the leade ins except for .006" because the chamber is .006" longer than the case.

[elmacgyver0]

I guess if it were me and I really wanted to know, I would ask Ruger.

[dtknowles]

I said "all but .006" of the driving bands" if SAAMI spec'd the case at .613" and the Anschutz reamer cuts the chamber at .619" then all of the driving bands are into the leade ins except for .006" because the chamber is .006" longer than the case.

Sorry, I misunderstood you.

Tim

[dtknowles]

I guess if it were me and I really wanted to know, I would ask Ruger.

I will see if that is possible. I just sent them a message and will report back.

Tim

[Kosh75287]

It's been MY experience that Ruger pistol & revolvers usually have GENEROUS chambers, though I've neverf been able to shoot better than any of them. My Police Service Six will chamber .38 S&W and 9mm Makarov rounds (I haven't tried to shoot Makarovs through it), for example. Could it be some aspect of the .22 LR auto design that the spent rounds are just enough bigger than unfired ones that their rims better engage the extractor?