Very short col/throat length problem?? advice needed - Page 2

Jim Watson · September 2, 2018, 09:51 AM

Then you have the problem of adherence to specs, any specs.
Somebody once did chamber casts of various .223, 5.56, Wylde, etc. barrels and found wide variations. Tight 5.56, large .223 seemed about as likely as spot on military or commercial.

cw308 · September 2, 2018, 06:59 PM

Ii can't remember the last time I measured or cared about OAL . Last year I tried 100 Amax Hornady 168 grain match bullets , was a big difference in shape compared the the Sierra 168 gr. MK . The case base to ogive measurement will be the same at the time of loading , no matter what bullet your using . I load one at a time . Like we all have mentioned in other posts , dummy rounds being tested in your chamber until it chambers without resistance. First with the case then using that perfect sized case , seating the bullet long and seating lower until it chambers with no resistance will get you a good starting point. Start with a safe starting powder load and work from there . As long as you follow all the steps in case prep reloading is pretty simple .

HiBC · September 2, 2018, 11:25 PM

Forgive me for not reading most of the previous posts.

First,you have a 1 in 9 twist.Beautiful for 69 gr bullets! Sweet spot.Varget is made in Australia.It probably has another designation.In my experience,its my "sweet spot" powder for 69 gr bullets.Your N-140 is in the proper burn rate zone.Its a subtle shade of grey difference.The N-140 should be fine.

Some folks say a 75 gr bullet will stabilize from a 1 in 9. But maybe not.I would not buy or load many without testing first.

I can't confirm it,please do not bet your face on it,but I have heard N-140 is the same powder as REloader-15. That might be wrong.

The Hornady handbook has an AR-15 match load section.From there,in my experience,REloader 15 is my #1 choice with a 75 gr Hornady BTHP Match.

Powder capacity? I load to about 2.250 to fit magazines. Powder to the base of the neck is not an issue for that LOA.If you are getting too much compression,just back off a grain or so.Your long range shot MIGHT need one more click elevation.So what?You will twist the knob anyway. A 10 or 12 inch drop tube may gain you a little compaction.

You might check to see what range you go subsonic.The transition can make a difference in stability.Accuracy may "hit the wall".

September 2, 2018, 11:25 PM	#28
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,286	Forgive me for not reading most of the previous posts. First,you have a 1 in 9 twist.Beautiful for 69 gr bullets! Sweet spot.Varget is made in Australia.It probably has another designation.In my experience,its my "sweet spot" powder for 69 gr bullets.Your N-140 is in the proper burn rate zone.Its a subtle shade of grey difference.The N-140 should be fine. Some folks say a 75 gr bullet will stabilize from a 1 in 9. But maybe not.I would not buy or load many without testing first. I can't confirm it,please do not bet your face on it,but I have heard N-140 is the same powder as REloader-15. That might be wrong. The Hornady handbook has an AR-15 match load section.From there,in my experience,REloader 15 is my #1 choice with a 75 gr Hornady BTHP Match. Powder capacity? I load to about 2.250 to fit magazines. Powder to the base of the neck is not an issue for that LOA.If you are getting too much compression,just back off a grain or so.Your long range shot MIGHT need one more click elevation.So what?You will twist the knob anyway. A 10 or 12 inch drop tube may gain you a little compaction. You might check to see what range you go subsonic.The transition can make a difference in stability.Accuracy may "hit the wall". Last edited by HiBC; September 2, 2018 at 11:37 PM.

September 2, 2018, 09:51 AM	#26
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,541	Then you have the problem of adherence to specs, any specs. Somebody once did chamber casts of various .223, 5.56, Wylde, etc. barrels and found wide variations. Tight 5.56, large .223 seemed about as likely as spot on military or commercial.

September 2, 2018, 06:59 PM	#27
cw308 Senior Member Join Date: September 2, 2010 Location: Plainview , Long Island NY Posts: 3,863	Ii can't remember the last time I measured or cared about OAL . Last year I tried 100 Amax Hornady 168 grain match bullets , was a big difference in shape compared the the Sierra 168 gr. MK . The case base to ogive measurement will be the same at the time of loading , no matter what bullet your using . I load one at a time . Like we all have mentioned in other posts , dummy rounds being tested in your chamber until it chambers without resistance. First with the case then using that perfect sized case , seating the bullet long and seating lower until it chambers with no resistance will get you a good starting point. Start with a safe starting powder load and work from there . As long as you follow all the steps in case prep reloading is pretty simple .