I have a custom .308 that shoots lights out with FGMM 168 ammunition. According to my RCBS precision mic, it has a throat length of .010. I actually get pressure signs with FGMM 175 grain ammo marked 7.62 x 51. Is it possible to lengthen the throat on a chambered barrel to allow me to seat heavier bullets such as the Berger 185 juggernaut and the 208 Amax further out of the case without jamming the lands?
Gunsmithing Lengthening the throat
- Thread starter glock63
- Start date
Re: Lengthening the throat
If it shoots so well with 168's why would you want to change anything?
If it shoots so well with 168's why would you want to change anything?
Re: Lengthening the throat
How did you measure the throat to determine it was .01?
How did you measure the throat to determine it was .01?
Re: Lengthening the throat
I would like to make use of heavier bullets to reach out to 1k. The 168's go subsonic just past 900 yds for me. Wind is a bitch here in SD as well. I most likely won't mess with it, but was curious.
I use this to measure my chamber and loaded ammo.
http://www.brownells.com/reloading/measu...9006314_d_20537
I would like to make use of heavier bullets to reach out to 1k. The 168's go subsonic just past 900 yds for me. Wind is a bitch here in SD as well. I most likely won't mess with it, but was curious.
I use this to measure my chamber and loaded ammo.
http://www.brownells.com/reloading/measu...9006314_d_20537
Re: Lengthening the throat
Not quite sure what the .01 is referring to, but there is only one way to lengthen your freebore, and it would be pretty cost prohibitive to do it yourself.
PTG sells a throating reamer with an adjustable stop, but you would be better off having a shop do it. First of all it would be quite an undertaking for a DIY, and if you EFF it up you are screwed.
Seems very strange that you are getting pressure with factory ammo, especially that stuff in 308, unless you have a very weird chamber the bullets shouldnt be into the lands anyway.
Not quite sure what the .01 is referring to, but there is only one way to lengthen your freebore, and it would be pretty cost prohibitive to do it yourself.
PTG sells a throating reamer with an adjustable stop, but you would be better off having a shop do it. First of all it would be quite an undertaking for a DIY, and if you EFF it up you are screwed.
Seems very strange that you are getting pressure with factory ammo, especially that stuff in 308, unless you have a very weird chamber the bullets shouldnt be into the lands anyway.
Re: Lengthening the throat
I would never try it myself. I was very surprised at the pressure signs as well. This gun does have a pretty tight chamber There was a pretty significant ejector mark, hard opening bolt, and the ejector actually sheared a bit of brass from the case head causing it to stick in the bolt body. Measuring the remaining rounds showed that the bullets were right at, or just in the lands. I seated them .005 deeper with my redding die set and the pressure signs are now much less pronounced.
I would never try it myself. I was very surprised at the pressure signs as well. This gun does have a pretty tight chamber There was a pretty significant ejector mark, hard opening bolt, and the ejector actually sheared a bit of brass from the case head causing it to stick in the bolt body. Measuring the remaining rounds showed that the bullets were right at, or just in the lands. I seated them .005 deeper with my redding die set and the pressure signs are now much less pronounced.
Re: Lengthening the throat
The short answer is yes.
This is exactly why throating reamers are made.
A smith will remove the barrel, chuck and indicate it in the lathe, then throat the chamber as desired.
Expect to pay ~1/2 to 2/3 as much as a basic rebarrel job costs in labor.
Your reasoning is sound. 168smks are excellent out to 500-600 yards, but leave much to be desired beyond. Other 168ish bullets are better, such as 155 scenars, or even 155 or 168 amaxs, but ultimately for 1000 yards, the 175+ pills are king.
What rifle and/or chamber have you got? Seems strange it has such a short throat.
The short answer is yes.
This is exactly why throating reamers are made.
A smith will remove the barrel, chuck and indicate it in the lathe, then throat the chamber as desired.
Expect to pay ~1/2 to 2/3 as much as a basic rebarrel job costs in labor.
Your reasoning is sound. 168smks are excellent out to 500-600 yards, but leave much to be desired beyond. Other 168ish bullets are better, such as 155 scenars, or even 155 or 168 amaxs, but ultimately for 1000 yards, the 175+ pills are king.
What rifle and/or chamber have you got? Seems strange it has such a short throat.
Re: Lengthening the throat
Don't lengthen your throat, go out and shoot and it will do it for you, that tool works great measuring headspace, but sux big time measuring distance to the lands, buy some 185s and loadem up, fine tune until it bug holes.
Don't lengthen your throat, go out and shoot and it will do it for you, that tool works great measuring headspace, but sux big time measuring distance to the lands, buy some 185s and loadem up, fine tune until it bug holes.
Re: Lengthening the throat
Yeah, I think I will forget this theory. Hate to mess with this rifle as well as it shoots. As far as which chamber I am not sure, but it was build by Karl Feldkamp in Michigan. I couldn't be happier with his work.
Yeah, I think I will forget this theory. Hate to mess with this rifle as well as it shoots. As far as which chamber I am not sure, but it was build by Karl Feldkamp in Michigan. I couldn't be happier with his work.
Re: Lengthening the throat
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: glock63</div><div class="ubbcode-body">Yeah, I think I will forget this theory. Hate to mess with this rifle as well as it shoots. As far as which chamber I am not sure, but it was build by Karl Feldkamp in Michigan. I couldn't be happier with his work. </div></div>
Karl is a friend of mine, and I'm planning on dropping off a barrel this week for fluting.
What are the details of your rifle... Action, bbl length, color, brake etc etc? He probably will remember it, and know the reamer specs. Or, call him. Its easy to get him on the phone...not so easy to get him to build you a rifle!
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: glock63</div><div class="ubbcode-body">Yeah, I think I will forget this theory. Hate to mess with this rifle as well as it shoots. As far as which chamber I am not sure, but it was build by Karl Feldkamp in Michigan. I couldn't be happier with his work. </div></div>
Karl is a friend of mine, and I'm planning on dropping off a barrel this week for fluting.
What are the details of your rifle... Action, bbl length, color, brake etc etc? He probably will remember it, and know the reamer specs. Or, call him. Its easy to get him on the phone...not so easy to get him to build you a rifle!
Re: Lengthening the throat
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: glock63</div><div class="ubbcode-body">Yeah, I think I will forget this theory. Hate to mess with this rifle as well as it shoots. As far as which chamber I am not sure, but it was build by Karl Feldkamp in Michigan. I couldn't be happier with his work. </div></div>
Karl is a friend of mine, and I'm planning on dropping off a barrel this week for fluting.
What are the details of your rifle... Action, bbl length, color, brake etc etc? He probably will remember it, and know the reamer specs. Or, call him. Its easy to get him on the phone...not so easy to get him to build you a rifle! </div></div>
No its not, but the wait was worth it. The man is an artist, and a hell of a nice guy. My name is Austin from SD. It is a remington SA in .308, 22 inch fluted barrel, green with black highlights in a McMillan A3-5. My main concern was the overpressure signs with the FGMM 175. The box was marked 7.62 x 51 instead of .308. Could that possibly have something to do with it? This barrel and chamber is very fast. My dope to 800 yards with FGMM168 comes out to 2800 fps.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: turbo54</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: glock63</div><div class="ubbcode-body">Yeah, I think I will forget this theory. Hate to mess with this rifle as well as it shoots. As far as which chamber I am not sure, but it was build by Karl Feldkamp in Michigan. I couldn't be happier with his work. </div></div>
Karl is a friend of mine, and I'm planning on dropping off a barrel this week for fluting.
What are the details of your rifle... Action, bbl length, color, brake etc etc? He probably will remember it, and know the reamer specs. Or, call him. Its easy to get him on the phone...not so easy to get him to build you a rifle! </div></div>
No its not, but the wait was worth it. The man is an artist, and a hell of a nice guy. My name is Austin from SD. It is a remington SA in .308, 22 inch fluted barrel, green with black highlights in a McMillan A3-5. My main concern was the overpressure signs with the FGMM 175. The box was marked 7.62 x 51 instead of .308. Could that possibly have something to do with it? This barrel and chamber is very fast. My dope to 800 yards with FGMM168 comes out to 2800 fps.
Re: Lengthening the throat
All military ammo is loaded for max speed and 1moa of accuracy. the cases are thicker so you will get more pressure..Keep that in mind when shooting 7.62x51 ammo
All military ammo is loaded for max speed and 1moa of accuracy. the cases are thicker so you will get more pressure..Keep that in mind when shooting 7.62x51 ammo
Re: Lengthening the throat
you may want to try some Berger 185VLD's. If you're worried about twist...they're fine for 1:12
you may want to try some Berger 185VLD's. If you're worried about twist...they're fine for 1:12
Re: Lengthening the throat
If you are going to reload for 1000 yards and want better bc, try the Berger 168 Hybrid. High bc and 168 bullet should fit pretty good on your throat
If you are going to reload for 1000 yards and want better bc, try the Berger 168 Hybrid. High bc and 168 bullet should fit pretty good on your throat
Re: Lengthening the throat
Ill check out both those bullets. Im running an 11 twist so I should be GTG there.
Ill check out both those bullets. Im running an 11 twist so I should be GTG there.
