.308 Bullet jump????

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   I did have one rifle.no, two, cut with the throat length determined by dummy rounds provided.  SOmething in the order of ogive + 0.002" or so, very short.  
I found no accuracy difference with these rifles, but did find in comparison to a long throat rifle that Sierra bullets, at least in 22, 30, and 33 caliber, are very length ( jump) tolerant with little or no accuracy degradation, and no appearent bullet deformation as evidenced by longer range groups.
  Hornady Amax bullets as one example haven't proved so forgiving in that regard.
My shooting partner has tried a couple other brands, some that are tolerent, some that are not.

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Mike McDonald Members Profile Send Private Message Find Members Posts Add to Buddy List Optics Journeyman Joined: September/01/2004 Online Status: Offline Posts: 605	Quote Reply Topic: .308 Bullet jump???? Posted: June/09/2009 at 18:50
	I did have one rifle.no, two, cut with the throat length determined by dummy rounds provided. SOmething in the order of ogive + 0.002" or so, very short. I found no accuracy difference with these rifles, but did find in comparison to a long throat rifle that Sierra bullets, at least in 22, 30, and 33 caliber, are very length ( jump) tolerant with little or no accuracy degradation, and no appearent bullet deformation as evidenced by longer range groups. Hornady Amax bullets as one example haven't proved so forgiving in that regard. My shooting partner has tried a couple other brands, some that are tolerent, some that are not.

sniper13 Members Profile Send Private Message Find Members Posts Add to Buddy List Optics Apprentice Joined: April/26/2009 Location: USA Online Status: Offline Posts: 145	Quote Reply Posted: June/12/2009 at 08:55
	Thanks guys....all good stuff........Mike I am in fact using an A-Max right now, just rolled some up to find out the optimal charge weight. With the Hornady HPBT Match, with them .005 off the lands and 44.5 Varget I am getting consistant .19''-.26''.
	pulling a trigger is easy....hitting your mark is intelligence

blmfgym Members Profile Send Private Message Find Members Posts Add to Buddy List Optics GrassHopper Joined: February/28/2008 Location: Ga. Online Status: Offline Posts: 9	Quote Reply Posted: June/22/2009 at 20:35
	Is there any data anywhere that will help analyize you group patterns to make them better? For example, does a vertical pattern indicate I should adjust powder, jump length, or brass trim, etc. and so forth?
	bye ya'll blmfgym

safariarms man Members Profile Send Private Message Find Members Posts Add to Buddy List Optics Apprentice Dolphin Overton Joined: June/28/2009 Location: K67BB Online Status: Offline Posts: 111	Quote Reply Posted: June/29/2009 at 19:44
	All are correct. Jump to the lands and grooves cannot be given as an absolute number as each rifle will react differently to that distance. I have had some rifles in some calibers that I had no choice, but to load to SAAMI specs. Others, if I wanted to load out to 0.02 inches off of the lands and grooves, I could not eject a misfire from the chamber (Savage Model 40 22 Hornet). While others, to load out that far, I ran out of room for seating the bullet. However, for the most part, most rifles will accomadate my demands and the best success I get, is 0.02 or even 0.01 off of the lands and grooves. But, again this is always rifle dependant. My rifles are confined to several brands, yours may be different. I have a Zastavia in a .308 that I loaded 0.03 inches off of the lands and grooves and it shoots less than 0.75 inch groups at 100 yards. I have never tried another distance, as this was more than adequate for hunting.

8shots Members Profile Send Private Message Find Members Posts Add to Buddy List Optics Master Joined: March/14/2007 Location: South Africa Online Status: Offline Posts: 2949	Quote Reply Posted: June/30/2009 at 04:24
	I have just increased the distance to the lands on my 308Win and it has improved accuracy. I am now 0.106 (no typo error) off the lands. Max length I can load is 2.818 " and I am seating to OCL of 2.712 ".

Steelbenz Members Profile Send Private Message Find Members Posts Add to Buddy List Optics Master ROLL TIDE ROLL Joined: January/03/2006 Location: Heart of Dixie Online Status: Offline Posts: 2667	Quote Reply Posted: June/30/2009 at 15:22
	Wouter, My Hornady manual says to seat 155s a 2.735 so your not that far into the case, how much powder are you loading percentage wise to what the case can hold?
	Be Bold enough to Succeed and Strong enough to not Fear Failure.

8shots Members Profile Send Private Message Find Members Posts Add to Buddy List Optics Master Joined: March/14/2007 Location: South Africa Online Status: Offline Posts: 2949	Quote Reply Posted: July/02/2009 at 04:32
	Steelbenz, I would have to check and will let you know. I think about 45gr is max it can hold and still seat the round. I am at 43.3 gr. The Somchem manual also called for a deeper seating then what I have been using, that made me test it out and it seemed the right way to go.