Need experienced answer to problem! Please.

[dgc940]

I have a tikka in .243 and the saami ocl is 2.710
well when using my stony point lenght guage I find with a 85 grn Nosler the Tikka has a very deep throat and the bullet fals out of the case! WOW DEEP
My magizine will acomadate up to 2.841.
My question is as long as I have a high case fill say 80-83% is it safe to load with
a OCL of say 2.750-2.780 Ive been concerned with this issue so I have been loading this bullet to 2.727 but would like to try 2.750

[Jim Watson]

If the SAAMI spec is 2.71" there is no problem loading to 2.75" as long as the bullet is secure in the case neck.

Bottleneck rifle cartridges are not nearly as affected by seating depth as a short straight pistol case. For pressure.
For accuracy, you will just have to shoot the gun.

[rwilson452]

I concur with Mr Watson. in fact the further out you place the bullet the larger the volume of the case which will lower the pressure spike. As long as you have enough neck tension to hold the bullet in place your good to go.

[dgc940]

Thanks for the answers! I kbow I can go to 2.750 and still have plenty of grip on the base.

[steve4102]

The rule of thumb I use is, At least 1 bullet dia. should be seated into the neck for proper neck tension. In your case there should be at least .243 in of bullet seated into the case. What sticks out is dependent on mag length and throat.

[Buckythebrewer]

Usually the thing that will bite you is having your bullet jammed(or touching the rifling)When your charges are near dangerous levels(or max).Having the bullet jump a little can help with High pressures.If you have a load that is already near dangerous levels and then you have the bullet touching the rifling or jammed into the rifling It can cause an already dangerous round to be way to HIGH in pressure(thats what I read anyways)..(like mentioned)If the neck has enough tension to hold the bullet you should be good..JMo
I am going to mention something that would be unsafe in someone elses rifle(using your ammo in there rifle) but here goes..I would use a neck sizing die(lee collet)and allow your brass to size to your chamber.Is it at all possible you are sizing your brass to much and maybe not giving your bullet enough neck to bite?I am probably way OFF but thought I would mention the possibility.

[Ammo Junky]

Tipicaly bullet jump matters little after .025" or so. If you can not get within .025" of the rifeling and still have .200 or more neck contact with the bearing surface, Just go ahead and seat to .010' below mag length. Youll get all the accuracy there is to be had with the (defecitive) :barf: long throat and you can feed from the mag. This assumes that at mag lengh that you have good neck grip. If not seat untill you do. I have a rem 308 with the lawyer throat. . I seated them as long as I could and got pretty close to a normal jump .015 or so. I then seated some at mag length .120" jump . There was no change in five shot accuracy. with 44.5gr varget and 165 gk and 168mk I consistantly got 1.0" five shot groups at either seating depth. If I have a gun with a decent throat I try .005, .015 and .025. If I have a remington 308 or other gun with the throat cut out, I under protest, surrender to the lawyers and just use the mag length.

Good luck
AJ

[castnblast]

I concurr with all the above. One other item; are you having accuracy issues which is forcing you to go with the longer COL? I ask, because in my experience, (not w/ .243, but w/ 7mm,25-06, 270) the longer COL did not gain a whole bunch of difference in my guns on paper. It did make a difference on my 25-06 as I developed throat erosion, and at that point, it did make a significant difference. My 22-250 which is new does not gain anything w/ varying lengths. But other guns are different. Here's some other food for thought I was thinking about yesterday, kind of an answer with a question...

Would a longer COL increase the life of a barrel by limiting bullet jump and thus reducing throat erosion? Things that make you go hmmm....It seems like it might, but I was curious what the engineers out there think on that matter...

[rgitzlaff]

Since you asked for an engineer's opinion, I'll give you one as a mechanical engineer. From what I understand about throat erosion is that it is mainly caused by the heat and pressure from the gases. Assuming you have equal charges in two cases with the bullets at different seating depths. When the gases hit the rifling, would there be any difference? Since seating the bullets further out can decrease pressure, then one could assume that the pressure would be less when the gases hit the rifling. That may just be an assumption though, since no matter the seating depth, the gases hit the rifling when the bullet is in the exact same position in the rifle,which is just past begining of the lands. This would make the volume behind it the same each time. If there would be any difference in throat erosion from seating depths, I would say that if anything, it would be virtually nothing. Impossibly too small to measure with any instrument or method. Does anyone else have a thought on this?

[dgc940]

I guess I should have mentioned in my original post that Im not having any group issues. It shoots way under MOA Im just having loads of fun with reloading and wanting to fool around with oal. and it seems like this Tikka dont care much about what powder I give it.
Thanks for all the replys!

[amamnn]

Without going into the lands, the seating differences you are talking about using would almost certainly not affect the downrange performance of your loads. You'll find that more and more rifle makers have gone over to the longer leade as more and more shooters try to emulate benchrest load that "jam seat" the bullet in the lands. What they are trying to do is make it impossible for your bullet to not "jump" in the rifle. When seating in the lands you eliminate that first burst of gas that passes the bullet as the neck opens and the bullet exits the case. This burst relieves start pressure in the chamber of the rifle. Apparently too many people have been injured or at least the rifle makers' lawyers thing too many will be injured using the above seating in factory rifles that are not built to the same standards as custom benchrest guns.

It is really questionable that factory rifles see any real accuracy improvement by running out the bullet seating beyond SAAMI middle specs. Most people do not load a very concentric round to begin with, and as the bullet seating is run out, the misalignment only becomes more pronounced. I'm told this is the source of the current misuse of the term runout as applied to bullet alignment. In any case, it seems you've already hit on the secret of successful reloading: if it works, don't fix it. But then we all love to tinker, or else why be reloading at all?

[dgc940]

The whole reason I wanted to play with Overall lenght is while loading for my other rifle a 22-250 I was loading the Barnes tripleshocks and they say set the bullet .50 to .70 off the lands and sure enough .55 off is where they shot best in my rifle?????