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Re: Tight throat? greydog #18216007 03/08/23
Joined: Mar 2007 Posts: 581 NC USA H Houser52 OP Campfire Regular
OP Houser52 Campfire Regular H Joined: Mar 2007 Posts: 581 NC USA	Originally Posted by greydog I have seen a number of five groove barrels in which the throat is defective, due to reamer deflection. In these barrels, there is evidence that the reamer has cut in the grooves but has not fully removed the lands. This is the result of one cutting edge of the reamer being unsupported by the others. The reamer essentially bounces back and forth as it cuts. This phenomena is made worse if the reamer is a bit dull. As I said earlier, this is most common when the throat is cut separately but it does happen with reamers which have an integral throater as well. The deflection is not huge, and to the naked eye, the throat appears normal. The amount of deflection is probably on the order of .001" or slightly less but it is still enough to leave enough land to contact the bullet. If one has the ability, it is possible to detect the deflection in the neck as well. In a throat which has this defect, the functional diameter of the throat will be somewhere near nominal bullet diameter or just a little less. Is it correctable? Yes, it is. The use of a spiral fluted throater, or a five fluted throater, will allow one to remove the remaining tops of the lands. The throat will still be a little weird because the grooves will but radiused differently than they should be, but the throat will work out OK. I have to emphasize, with the right tooling, the right set up, and the right technique, this will not happen. It is my opinion though, Ruger has an issue in one or more of these areas; at least in this chambering. GD I still haven’t called Ruger about my rifle but I reread your post a couple times and think you maybe correct on your diagnosis. Since my last post I took my rifle to a local gunsmith and had him take a look at my rifle with his borescope. He said nothing looked abnormal but when he smoked the bullet and inserted into the chamber, he had concerns about the way the bullet contacted the lands. A couple contact points were very obvious with the rest either very faint or you couldn’t even see them. This may explain why I can feel two different points where the bullet contacts the lands. I have also been researching throaters and may go this route instead of going back and forth with Ruger. Looks like the PTG Uni-throater might be what I need just to “clean up” the throat.

GB1

Re: Tight throat? Houser52 #18219137 03/08/23
Joined: Apr 2004 Posts: 42,697 Southern Oregon USA S Seafire Campfire 'Bwana
Seafire Campfire 'Bwana S Joined: Apr 2004 Posts: 42,697 Southern Oregon USA	I didn't see it, hence why I am asking... How you tried another bullet? or a different bullet weight? "Minus the killings, Washington has one of the lowest crime rates in the Country" Marion Barry, Mayor of Wash DC “Owning guns is not a right. If it were a right, it would be in the Constitution.” ~Alexandria Ocasio Cortez

Re: Tight throat? Houser52 #18219174 03/08/23
Joined: Mar 2007 Posts: 581 NC USA H Houser52 OP Campfire Regular
OP Houser52 Campfire Regular H Joined: Mar 2007 Posts: 581 NC USA	Yep, the Hornady 105 BTHP and the Berger 105 Hybrid. All have to be seated way short of what they should be.

Re: Tight throat? Houser52 #18220363 03/09/23
Joined: Jun 2004 Posts: 7,165 G greydog Campfire Tracker
greydog Campfire Tracker G Joined: Jun 2004 Posts: 7,165	Originally Posted by Houser52 Originally Posted by greydog I have seen a number of five groove barrels in which the throat is defective, due to reamer deflection. In these barrels, there is evidence that the reamer has cut in the grooves but has not fully removed the lands. This is the result of one cutting edge of the reamer being unsupported by the others. The reamer essentially bounces back and forth as it cuts. This phenomena is made worse if the reamer is a bit dull. As I said earlier, this is most common when the throat is cut separately but it does happen with reamers which have an integral throater as well. The deflection is not huge, and to the naked eye, the throat appears normal. The amount of deflection is probably on the order of .001" or slightly less but it is still enough to leave enough land to contact the bullet. If one has the ability, it is possible to detect the deflection in the neck as well. In a throat which has this defect, the functional diameter of the throat will be somewhere near nominal bullet diameter or just a little less. Is it correctable? Yes, it is. The use of a spiral fluted throater, or a five fluted throater, will allow one to remove the remaining tops of the lands. The throat will still be a little weird because the grooves will but radiused differently than they should be, but the throat will work out OK. I have to emphasize, with the right tooling, the right set up, and the right technique, this will not happen. It is my opinion though, Ruger has an issue in one or more of these areas; at least in this chambering. GD I still haven’t called Ruger about my rifle but I reread your post a couple times and think you maybe correct on your diagnosis. Since my last post I took my rifle to a local gunsmith and had him take a look at my rifle with his borescope. He said nothing looked abnormal but when he smoked the bullet and inserted into the chamber, he had concerns about the way the bullet contacted the lands. A couple contact points were very obvious with the rest either very faint or you couldn’t even see them. This may explain why I can feel two different points where the bullet contacts the lands. I have also been researching throaters and may go this route instead of going back and forth with Ruger. Looks like the PTG Uni-throater might be what I need just to “clean up” the throat. I can't emphasize enough, if you are cutting throat in a five groove barrel, with a throating reamer, you will need to use a spiral fluted or a five fluted reamer, and with a closely fitting pilot. GD

Re: Tight throat? Houser52 #18220654 03/09/23
Joined: Mar 2007 Posts: 581 NC USA H Houser52 OP Campfire Regular
OP Houser52 Campfire Regular H Joined: Mar 2007 Posts: 581 NC USA	Thanks greydog. I went to a nearby gun shop yesterday looking for powder and to get some info on their yearly groundhog/ egg shoot. We got to talking about my rifle and they suggested a local rifle builder, Plainsview Precision in Lawndale, NC. All of the shop’s employees are shooters and have used him at some point. I gave the builder a call and he is going to have a look at it. He’s just had knee surgery and will be out of the shop for a month.

IC B2

Re: Tight throat? Houser52 #18221682 03/09/23
Joined: Sep 2004 Posts: 8,125 S.E. Alaska MuskegMan Campfire Outfitter
MuskegMan Campfire Outfitter Joined: Sep 2004 Posts: 8,125 S.E. Alaska	Originally Posted by Houser52 All have to be seated way short of what they should be. And where, praytell, is this?

Re: Tight throat? MuskegMan #18222428 03/09/23
Joined: Mar 2007 Posts: 581 NC USA H Houser52 OP Campfire Regular
OP Houser52 Campfire Regular H Joined: Mar 2007 Posts: 581 NC USA	Originally Posted by MuskegMan Originally Posted by Houser52 All have to be seated way short of what they should be. And where, praytell, is this? 6mm Creedmoor SAAMI maximum COAL length is 2.800” Hornady reloading manual- 105gr and 108gr loads tested at 2.790” COAL In my rifle, 105 BTHP, touches at 2.625” COAL. I can force the bullet in deeper to 2.780” COAL 108 ELD-M, touches at 2.675” COAL. I can force the bullet in deeper to 2.742” COAL All measurements are short of the SAAMI 2.800” I hope the issue is what greydog posted earlier and the gunsmith can get it corrected. I have only shot 1 of the factory ELD-M and didn’t have any pressure signs but I won’t shoot anymore until it gets checked out. I have been shooting my 105 BTHP loads and they do pretty well. Last edited by Houser52; 03/09/23.

Re: Tight throat? Houser52 #18224638 03/10/23
Joined: Jun 2016 Posts: 9,571 Kentuck G gunzo Campfire Outfitter
gunzo Campfire Outfitter G Joined: Jun 2016 Posts: 9,571 Kentuck	These dimensions sound nearly identical to the barrel that Ruger took off of my rifle, just before installing one with a correct SAAMI chamber. Maybe they saved my old barrel & put it on your gun. They're a phone call away & know about the problem, whether they'll admit it or not.

Re: Tight throat? Houser52 #18632105 08/01/23
Joined: Mar 2007 Posts: 581 NC USA H Houser52 OP Campfire Regular
OP Houser52 Campfire Regular H Joined: Mar 2007 Posts: 581 NC USA	Update- I finally got another opinion from a different gunsmith. As someone said earlier and my gunsmith verified, it looks like the lands were not fully removed when the chamber was cut. I called Ruger today and explained everything. They wanted to check it out and sent me a shipping label. I got it boxed up and shipped this afternoon. Since we’re both in NC they should have it in a day or so. Hopefully they can get the chamber corrected the first time and it’s still as accurate as it was with the bad chamber.

Re: Tight throat? Houser52 #18678819 08/17/23
Joined: Mar 2007 Posts: 581 NC USA H Houser52 OP Campfire Regular
OP Houser52 Campfire Regular H Joined: Mar 2007 Posts: 581 NC USA	After about 2 weeks from shipping my barrel to Ruger I got it back yesterday. They replaced the barrel. With the newly replaced barrel I was anxious to see how it performed. I tore it down, cleaned under the pic rail and re-torqued the screws, cleaned the action, ran a few clean patches down the bore and re-torqued the action screws. Mounted the scope and torqued everything to the mfg. recommendation. Using the Stoney Point gauge I checked where the Hornady 108 ELD-M bullet contacted the lands, 2.842” avg. as opposed to the original barrel at 2.791”. There was no resistance when checking the OAL, just a hard stop. So far so good. I already had a few rounds of 85 gr. Sierra SP that I had previously loaded so I decided to use them to sight in. The first shot was on paper at 50 yds so I made and adjustment and backed up to 100 yds. After a couple more shots I had it pretty well dialed in with the 85 Sierra SP. So far it looks like the accuracy of the new barrel is good with the 85s and I’ll be checking the 108 ELD-M later to see how they do. Here is the 85gr Sierra. I know, I know that it’s only two shots but it’s incourging. Last edited by Houser52; 08/17/23.

IC B3

Re: Tight throat? Houser52 #18678924 08/17/23
Joined: Jun 2004 Posts: 7,165 G greydog Campfire Tracker
greydog Campfire Tracker G Joined: Jun 2004 Posts: 7,165	Excellent ending. Good on Ruger for changing the barrel. GD

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