I guess this is the right forum to ask this on......I have two short action rifles that I am trying to work up a load with one of the new bonded style bullets (Scirocco-inner bond-accu bond). My problem is that to get any of these three close to the lands of three different barrels the ammo is far longer than will feed from the magazine. I had the mags massaged out but another .020 was about it and at 2.900 max the above mentioned bullets are from 2.918-2.944 overall at .020 off lands. It seemed that pushing off the lands till they fed greatly reduced accuracy as groups opened up. Two barrels are factory and one is a Douglas, I called Pac-Nor and they tell me they have only two reamers for a 7mm-08 caliber and can't control throat length as its cut with the chamber. Is it just me or are these latest bullet offerings very slim and long for weight? My barrels will handle ballistic tips and paritions no problem but my faith in BT's was wrecked several years ago and the paritions just won't group in either gun with any barrel combo. Pac Nor tells me that setting close to the lands is highly overrated and borders on BS with powder charge adjusting able to tighten groups at any distance from lands necessary to feed. Perhaps they are right as they tell me they are starting to hear from a lot of customers not happy with current throat lengths on short action barrels. My gunsmith has suggested buying a custom reamer that will keep the bonded bullets within magazine length OAL. I realize that will push the bullets deeper into the case and effect powder capacity but I'm not filling cases now and load more for accuracy than velocity. Changing to a long action gun chambered for the 7mm-08 would work for some but I already have my guns and prefer to work something out with what I have. Pac Nor also tells me that the point will probably be moot as their barrel will probably shoot paritions (my bullet of choice) excellant and I'll have no interest in pursuing the bondeds at that point. This is true and if I can get good groups (1/2-3/4") with paritions I would be happy and set. Are other guys hitting this problem as the bullet makers seem to allude to when called? Seems 2.900 is a pretty decent magazine length for a short action gun to be having such trouble. Gets old buying $20+ boxes of bullets only to find they won't get near the lands. Would be happy to hear of any experiences or advice.......thanks

woods

It Too bothers the heck out of me but I just looked away and started fiddling with the powder charges.

Pacnor is probably right. I've got some rifles that will shoot quite good when the bullets have quite a jump. I just make them short enough to feed and go with it. You'll be surprised how accurate you can be without touching the lands. I've shot groups below 1/2 moa many times with loads that were just loaded to mag length.

Just think about Weatherby's Freebore. I've seen some MKVs that were very accurate for hunting rifles(sub 1/2 moa at 200 yards) and I bet those bullets jumped a 1/4 inch!

I do feel there is a slight bit of myth to the kiss the lands theory. Myth or not, I still load em' almost touching the lands in all of my rifles that allow it.

Reloader

Sounds like Pac Nor may be bordering on B.S.

That was kind of Noslers response also.....they do admit the latest bonded bullets are very hard to seat near the lands and feed in a factory short action gun but feel powder tuning is less able to make up the difference in accuracy that keeping close to the lands provides. They also suggested a short throat reamer as the best approach if the new barrel also fails to deliver good accuracy with the parition. Guess I'm tween a rock and a hard place if I can't get my hands on a barrel that happens to put the paritions in tight groups. Should have the Pac Nor by mid next week so I will soon see.

woods

I'm not at all sure that there's any connection between bonded bullets and throat length.

Further I'm not sure that the supposed connection to throat length (within reason) and any bullet at all is horribly relevant.

quote:

I'm not at all sure that there's any connection between bonded bullets and throat length.

Only connection would be that they are longer and slimmer for weight and tend to seat out a lot further to contact the rifle lands. Nosler-Hornady-and Pac Nor knew exactly what I was talking about and seemed aware of this situation.

quote:

Further I'm not sure that the supposed connection to throat length (within reason) and any bullet at all is horribly relevant.

Good enough.....I doubt some benchrest or target shooters would concur.......but thanks for the imput.

woods

woodseye, so is your thought that the barrel mfgs. have lengthened throats because bullets are longer than many previous ones? I can tell you that for a long time, before I ever read an ad about a bonded core bullet, I owned several rifles, both factory and custom, that a bullet would not get to the lands and have a COL that would function in the magazine.

Today I still have some that do, and some that don't. While it may be easier to get superb accuracy with bullets seated at or near the lands, I have plenty that shoot splendidly that have plenty of jump, and know several bench rest shooters that have rifle of both ilks also. Perhaps this is unusual, but I haven't really worried about it.
My thought had been that the slightly longer bonded bullets would make it easier to get to the lands, i.e. if you seated the bullets that same amount into the case, the longer bullets would be closer to the lands--maybe I'm missing something.

I would like to be able to get to the lands on all my rigs, but I can't. I actually have a few that the lands are reasonably close on though, and I won't/can't shoot Barnes XXX's cause there isn't enough jump to the lands--go figure.

No I don't think manufactures have done anything with throat length. I believe the newer bonded plastic tipped bullets need to be loaded out a lot further to contact lands and the resulting OAL of the cartridge is too long for a lot of short action magazines. This would not be an issue in single shots or long action guns with the same short action caliber. I understand there are given specs the makers adhere to but bullet makers are creating bullets that simply need a good bit of jump to reach the lands when loaded to feed in under 3" short action mags. I realize that you can simply seat the bullet deeper into the case to reach feed length like factory ammo and try to tune the group size in by raising and lowering powder charge within safe reason. This is sort of doing the same thing as moving the bullet seating depth in and out....its altering the point at which the bullet exits the barrel in relation to its harmonics. My only question was "is this is as effective as OAL tuning", and the answer from different companies is varied. Some tell you OAL tuning is more myth than fact while others claim that simply changing charge weight will do the same thing,still others agree that OAL tuning is quite important in some rifles and calibers and can't be ignored if sub MOA is a goal. I understand freebore and up to your caliber dia. bullet jump and how some guns will shoot very well with this, its just I haven't had any real sucess with my 7mm-08 when making the bullet jump .040 or more to the lands. The fellow at Nosler made the most sense and I'm sure hes right that a shorter throated reamer would really be the ticket for what I'm trying to do. I could maintain the .400-.500 accuracy of the gun while still maintaining under 2.880 OAL length for trouble free feeding.

woods

Hey woodseye

I'm a little surprised that you can seat the BT's where you want and the AB's won't seat at the same distance from lands. Those 2 bullets are supposed to be almost identical and have had the same measurements the few times I've measured a BT (I don't shoot them much either). Sounds like you are close enough that for sure you could shoot the TSX's or the TBBC's.

You didn't say what grain bullet you are shooting, but I have found that a heavier TSX in the same caliber actually has a shorter OAL than a lighter one. They reduce the curve from ogive to meplat in order to put more weight on the bullet. For instance in a 270 I used to have I could seat the 140 gr TSX within .05" of the lands and still fit the mag but could not with the 130 gr.

If bonded is the key word in what you want you can always shoot the TBBC's or the Northforks. I always got excellent accuracy from the TBBC's when I could talk myself into paying that much for a bullet. They definitely are more accurate in my rifles than the Partition. They perform flawlessly in the field also.

The Swift A-Frame is another candidate but the accuracy for me has always been equivalent to the Partition.

I never could get the Scirrocco to shoot anyway but it's a shame you can't shoot the Accubond. TSX's are more accurate than the Accubond's, IME, but some don't like the high-velocity pencil-throughs at close range some claim. Just aim to hit bone and they work great and don't ruin much meat.

Woods,

I just spent the past few months putting together a load which uses both BT and AB's. It's a 30-06 Ackley, so yes it is a long action, but I started all my initial load devlopment .005" into the lands. Once I got through the 300 yd Audette ladder and settled on a powder charge, I then played with the seating depth in .005" increments. I found that .015" off the lands, thus far, worked quite well. I'm getting 1/2 to 3/4 MOA out to 600 yds with both bullets.

So, what I'm saying is, irregardless of mag length, single load your loads as you work them up and prove, to yourself, wether or not your rifles really desire "on the lands" or if some distance off will be more accurate.

Big Al....I did almost exactly what you have done and the AB shot its best at .018 off lands while the BT was .020. At .018 off the lands with a bullet that is 2.944 to the lands......see what I mean? It still needs to be 2.926 OAL for best accuracy and my magazine is getting really really tight at 2.890. I hunted last year with one AB loaded into the chamber and several BT's in the magazine for any follow-ups if or when needed. This worked OK and the gun preformed flawlessly in a one shot kill on my buck. I just would prefer to be able to carry one group of loads and not worry about grabbing two different loads everytime I head back into the woods,much less keeping them in the correct order when loading.

Reloader.....140 gr.BT's are on the lands at 2.875 OAL and give me lots of leeway to set them anywhere I so desire for distance off lands. 140gr.AB's are at 2.944 and 139gr.inner bonds are at 2.921. So you see there is quite a difference in OAL to the lands with these different type but almost identical weight bullets. Paritions sit at 2.859 so are also no problem.....its just I can't get very good accuracy either (1 1/2" groups at 100yds) I have had several other people now suggest the same thing you just did to me, that is, that the heavier weight AB's and IB's may work for me because of a difference in ogive to meplat taper. This I have not had a chance to actually try and compare. A good idea and one I may end up trying before this is over. I was hoping some fresh perspective would come of this post and thats one good idea. TBBC's are another idea I hadn't considered.

woods

I don't think there is a hard and fast rule about what distance to lands works. As with most things in guns and reloading - it depends on the gun and the load. See posts from our esteemed member "1894" (not exact name), he apparently has (several?) rifles which work well with a long distance to lands.

Quite apart from what works in the individual rifle, it is often a pain in the posterior with long throats. I also like seating relatively close to lands, and in factory guns, this often remains a pipe dream. Even in guns with mags long enough to harbour the loaded round, sometimes you run out of seating depth in the case neck to reach lands. I suppose one could accept such "sloppy" chambers in a factory gun, but I have (sadly) also experienced long throated guns in custom barrels...

It is true, that you can't measure throat depth on a reamer, but why on earth anybody would have a reamer cut with such long throats is beyond me. The only real measure seems to have your onwn personal reamers specified and cut - to the tune of about $150 per new cartridge you want to have a barrel chambered for. Sad state of affairs, really.

- mike