I need a little help. Despite my age (old + a few), I'm new to the sport (both shooting & reloading). I'm retired military, and a precision CNC machinist in my "second life" (although not a gunsmith by any stretch). I have a "situation" which prompts me to seek the wisdom/advise of more experienced enthusiats & gunsmiths.
I recently purchased a Rem 700 BDL in 22-250 cal. My initial factory ammo choice is Hornady Superformance Varmit, 50-gr V-Max, 4,000 fps (claimed) with a C.O.L. of 2.340" (0.010" less than SAAMI max). Although purchased initially for varmit hunting, I'm going to reload with the intent of getting the most accuracy out of the gun as possible, not necessarily the highest velocity. I've been reading (a lot!) about ballistics (internal, external & terminal) and reloading, and have outfitted a respectable reloading bench.
Today, I was disappointed. Here's why: I've read that the best accuracy usually occurs when a bullet is seated close to the rifling. Zero inches of clearance, up to .030" clearance is often quoted, although I've read comments that more clearance sometimes produces good results. I measured the clearance of my chosen factory ammo, and was shocked to find that, in my arm, it has 0.147" clearance from factory's bullet seating depth to the engagement of the rifling. Granted, the V-Max bullet has a sharp ogive (which increases the clearance), but this is MUCH more than I expected, and 10 times the clearance I was hoping to achieve.
The factory round is already close to the SAAMI max C.O.L., but my magazine & receiver is plenty long enough to extend my rounds beyond the SAAMI max .... BUT ..... placing the bullet near the rifling means only 0.125" of the bullet is gripped by the case. I'm guessing this is way too little.
So ... I want to shorten the throat, but the only two ways to acheive this is to move the rifling backwards (not possible!), or to move the chamber forward. Since it's not possible to replace rifling that has been reamed away by the factory, my only option is to remove the barrel, shorten the breach end by 0.100" and then re-ream the chamber to the correct depth (by extending it by the same 0.100" the barrel was shortened). The intended result would be simply shortening the throat (free-bore) by 0.100", thus allowing me to seat my chosen bullet (Hornady V-Max 50 gr.) MUCH closer to the rifling. I know this is an over-simplified explanation, and there are several other concerns & dimensions to maintain, but you get the idea. (I know that a new custom barrel is also an option, but I'm calling that Plan-B.)
Question: Is this a ludicrous thought .... or something that just may work if done correctly? (As a machininst, I own a precision lathe capable of the task, and plenty of inspection equipment, but that doesn't make it a wise venture......)
Intelligent comments born of wisdome and/or experience would be GREATLY appreciated. Redneck jabs fueled by an alcohol induced stupidity can be kept to one's self.
Thanks in advance (and sorry for the long post, but better too much info than not enough)
Mike
I recently purchased a Rem 700 BDL in 22-250 cal. My initial factory ammo choice is Hornady Superformance Varmit, 50-gr V-Max, 4,000 fps (claimed) with a C.O.L. of 2.340" (0.010" less than SAAMI max). Although purchased initially for varmit hunting, I'm going to reload with the intent of getting the most accuracy out of the gun as possible, not necessarily the highest velocity. I've been reading (a lot!) about ballistics (internal, external & terminal) and reloading, and have outfitted a respectable reloading bench.
Today, I was disappointed. Here's why: I've read that the best accuracy usually occurs when a bullet is seated close to the rifling. Zero inches of clearance, up to .030" clearance is often quoted, although I've read comments that more clearance sometimes produces good results. I measured the clearance of my chosen factory ammo, and was shocked to find that, in my arm, it has 0.147" clearance from factory's bullet seating depth to the engagement of the rifling. Granted, the V-Max bullet has a sharp ogive (which increases the clearance), but this is MUCH more than I expected, and 10 times the clearance I was hoping to achieve.
The factory round is already close to the SAAMI max C.O.L., but my magazine & receiver is plenty long enough to extend my rounds beyond the SAAMI max .... BUT ..... placing the bullet near the rifling means only 0.125" of the bullet is gripped by the case. I'm guessing this is way too little.
So ... I want to shorten the throat, but the only two ways to acheive this is to move the rifling backwards (not possible!), or to move the chamber forward. Since it's not possible to replace rifling that has been reamed away by the factory, my only option is to remove the barrel, shorten the breach end by 0.100" and then re-ream the chamber to the correct depth (by extending it by the same 0.100" the barrel was shortened). The intended result would be simply shortening the throat (free-bore) by 0.100", thus allowing me to seat my chosen bullet (Hornady V-Max 50 gr.) MUCH closer to the rifling. I know this is an over-simplified explanation, and there are several other concerns & dimensions to maintain, but you get the idea. (I know that a new custom barrel is also an option, but I'm calling that Plan-B.)
Question: Is this a ludicrous thought .... or something that just may work if done correctly? (As a machininst, I own a precision lathe capable of the task, and plenty of inspection equipment, but that doesn't make it a wise venture......)
Intelligent comments born of wisdome and/or experience would be GREATLY appreciated. Redneck jabs fueled by an alcohol induced stupidity can be kept to one's self.
Thanks in advance (and sorry for the long post, but better too much info than not enough)
Mike
