Accubond Jump?

[rodell]

What kind of jump do you usually end up with Accubonds? I'm trying to get .30-06. 180 grain AB's to shoot in my Blaser R8 and I've not found a load that works very well at all. I haven't ever had to give up on a bullet before and I bought several boxes so I can keep going.

I've been keeping the AB out near the lands where I usually put conventional bullets due to the length of the 180's. Even varying the depth near the lands doesn't seem to matter much so I am thinking AB's may be more like the Barnes.

 

[DrMike]

Virtually all the ABs I have used have about 0.100 inch jump to the lands. There are a few instances when I used slightly less (say, 0.70 inches), but almost always it has worked out to 0.100 inch.

 

[MrMinks2]

I am using the 180 gr. Accubonds in my Remington 700 .30-06 and am having success at 0.125" off the lands backed up by 61.5 grs. of RL 22. Groups are consistently sub moa at 100 yds.

 

[filmjunkie4ever]

I don't remember exactly how far off the lands I had to seat but I always got better accuracy in my Model 70 Winchester in .30-06 by seating the Accubonds deeper into the case. The closer to the lands, the worse they seemed to shoot in my rifle.

I think I was seating 3.300" or 3.310" COAL.

Dale

 

[MAinAR]

Virtually all the ABs I have used have about 0.100 inch jump to the lands. There are a few instances when I used slightly less (say, 0.70 inches), but almost always it has worked out to 0.100 inch.

+1 here too.

 

[rodell]

Great info. On the 30-06, that puts the 180 grain bullet well into the case. With 61.9 grains of MRP I began to see some pressure signs (flattened primer). The throat is pretty short on this Blaser, I contact the lands at 3.345" COAL, which is only .005" beyond the SAAMI maximum COAL.

I'll set a length closer to 3.245 and back off a few grains and try again.

 

[SJB358]

Virtually all the ABs I have used have about 0.100 inch jump to the lands. There are a few instances when I used slightly less (say, 0.70 inches), but almost always it has worked out to 0.100 inch.

Same here... I start at .050" out of principle but usually end up .070-.125".

 

[truck driver]

Thanks for this post. I think I now understand what it takes to get the AB to shoot. I've been worrying with them in my 35 AI and just haven't been able to get where I want them to shoot though everyone has liked my groups I just haven't been satisfied with them. With the new bedding job and the info here I might get what I want out of them.

 

[ElmerThud]

I load my .25-06 Blaser rounds at .045" from the lands. The seating depth took some finding, but I got there and regularly have .25" MOA @ 100yds. with the the 110gn Nosler AB bullet.

I can easily understand the many users where further jump is required and personally have never found seating Nosler bullets close to the lands very helpful.
Scotty's suggestion to start at .050" is IMO a very good place to start.
Cheers.

 

[truck driver]

One question so I'm sure what your doing with measuring the jump off the ogave of the bullet and not the tip?
Saami for a 35 Whelen AI is 3.340" off the tip of the bullet but off the ogave it's 2.592" with a 200gr AB. (.808" from tip to ogave)
Measuring off the lands the oal to the ogave could be 3.531" oal and 2.782" off the ogave (my rifle chamber). So if I start with a oal of 3.431"oal off the tip or 2.682" off the ogave these rounds won't fit my magazine which is 3.400", to fit magazine I would have to go with a .131" jump to the lands. Is this too deep to get the AB to shoot good in my rifle?

 

[SJB358]

Nope, not at all. Found plenty of good loads that'll shoot just fine at that distance with the ABs.

 

[truck driver]

Thanks Scotty I just wasn't sure I under stood what was being said. I had been confused when you were telling me to shorten my loads up when they were at 3.395" oal off the tip to tighten up the groups. I'm learning to reload all over again since I came here.

 

[SJB358]

Same here Rodger. I'm still learning from you all.

 

[jimbires]

if the magazine length is shorter than the lands , I start at mag length and work shorter . this way you only have one direction to go, to find accuracy .

 

[rodell]

I always specify and discuss the distance to the lands with COAL, as almost everybody can relate to that. I always measure both, and keep the data in my notes. Getting the Ogive distance to the lands off the chamber print takes some doing.

 

[truck driver]

I always specify and discuss the distance to the lands with COAL, as almost everybody can relate to that. I always measure both, and keep the data in my notes. Getting the Ogive distance to the lands off the chamber print takes some doing.

rodell, what I did today was blacken a 200gr AB and seat it in a powder less decapped case overly long so that when I chambered it I would get a crush fit to the lands. I measured 5 bullets to see if they were all the same length from tip to base. The plastic tips make that easy since they don't deform easy. I then seated the bullet to Saami OAL off the tip, 3.340" and then measured it with a Hornady comparator to get the COAL off the Ogave to check that all my loads were seated the same depth.
All rifle chambers are not the same so the prints only tell you what it should be and not what each individual rifles chamber is.
I did learn that the .358 200gr AB and the 225gr AB both have the same length from Ogave to tip while I was experimenting today, I don't have my notes in front of me but I think it was .808".
Is this the right way to do it, I don't know but I figured I needed a starting place and this was the best I could come up with.

 

[Wyo7200]

142 gr ABLR 6.5 Creed = .050
160gr AccuBond 7mm Rem Mag = .131
110gr AccuBond 25-06 = .050
129gr ABLR .260 Rem = .100
________________________

If I change my 7mm Rem Mag to be .1 (.030 deeper)- Could I drop the charge .3-.5 of a grain and still achieve the OBT? I've had this thought for while that the adjustment of tenths of a powder charge can mitigate or compensate the seating depth factor. You can fiddle with a calibrated QL and get multitude's of combinations to achieve an OBT. I guess one way to find out is to load a bunch of rounds up that are adjusted accordingly (+/-.2gr powder per .05 seating depth change maybe depending on caliber?) and see if the velocity is consistent and groups are precise at the range. Someday when I retire I may do it just to see.

 

[rodell]

As usual, the net.wisdom here was right. I found very tight groups with an OCW charge at .080" and .050" from the lands. I was way too close before with the AccuBond.

I ended up with 61.3 grains of MRP (or RL-22, if you prefer) and a solid load.

 

[rodell]

I always specify and discuss the distance to the lands with COAL, as almost everybody can relate to that. I always measure both, and keep the data in my notes. Getting the Ogive distance to the lands off the chamber print takes some doing.

rodell, what I did today was blacken a 200gr AB and seat it in a powder less decapped case overly long so that when I chambered it I would get a crush fit to the lands. I measured 5 bullets to see if they were all the same length from tip to base. The plastic tips make that easy since they don't deform easy. I then seated the bullet to Saami OAL off the tip, 3.340" and then measured it with a Hornady comparator to get the COAL off the Ogave to check that all my loads were seated the same depth.
All rifle chambers are not the same so the prints only tell you what it should be and not what each individual rifles chamber is.
I did learn that the .358 200gr AB and the 225gr AB both have the same length from Ogave to tip while I was experimenting today, I don't have my notes in front of me but I think it was .808".
Is this the right way to do it, I don't know but I figured I needed a starting place and this was the best I could come up with.

That method is fine, as long as you don't have too much neck tension on your test case. You can easily jam the bullet into the lands and end up wit ha measurement that is off quite a bit. The easiest way is to use the Hornady tool and one of their cases to get repeatable measurements. Even then, an average of five tries is a good thing.

 

[jimbires]

the problem I see with the hornady gauge is ,we reloaders know new brass does not fit our chambers worth a darn . it's way to short from case head to shoulder . if you are not using a piece of brass that has been fired in that chamber , until it is fully expanded ,it does not fit the chamber that well . taking a new piece of brass ,like the hornady tool uses , and pushing it forward in the chamber until the shoulder hits has to have a few, or more than a few , thousandths of clearance between the bolt face and the brass case . how much bullet to rifling clearance is all ready built in by using this tool ?