As some of you may remember, I'm new and you guys helped me get started this spring. I've been off the forum for some time because the computer guys have been messing with some software that blocks this site from our server because weapons, bombs, yada yada is in the description.

I don't know how long I'll be back on, but I'm here for now and need some help. I followed advice I got from this board and created a "dummy" round that I could use to determine an OAL that would seat a bullet to the lands of my Remington Model 7 in 300 Rem SAUM. I may misquote a number because I wasn't expecting to get to this site today, but I'll get close: The OAL of that dummy round measured with an RCBS digital caliper was 2.945". I followed the advice and backed off 1/16" for a starting place. That meant my rounds would have to be 2.830". My Speer manual says maximum OAL for this cartridge is 2.825". What should I do? I know that it probably will not be safe to go past that max OAL. Tell me how you guys start a brand new gun...

I know I'm cramming a lot in a post, but I may not be able to access this site again so, please help. You said I'd have more questions after I got started and you were right!! Here is my next one: I was trying to achieve 2.830 and I had everything come out of my Rockchucker. I was loading segregated new remington brass. I'd grouped the brass according to exact measurement. I'm loading Nosler Partition 180 grain bullets and no two measure the exact same length. So how much tolerance is accepted? I realize that .001 is not much, but many guys tell you the OAL their rifle loves. How do you get your rounds the same. I would have thought bullets were closer to the same length, but after measuring a few with my caliper, I found them to be irregular as well. Do I need to segregate the bullets too?

One final note: If I don't respond to this post tommorrow, please forward suggestions to jamiemoss@adair.k12.ky.us

Thanks guys!!

Basically, don't worry at all about what that Speer, or any other manual, may say about max. OAL for any cartridge. They are quoting SAAMI specs, and those might or might not apply to your rifle. Even changing bullet designs will change the OAL of ammo which is right for your rifle. The method you used is correct, as long as it does not result in an OAL which prohibits you from using your magazine.
Since you are hopefully working up the optimum powder/bullet load combination for your particular rifle, you are automatically compensating for the potential differences in pressure and velocity effects of bullet seating depth!

This is generally no problem for me these days, because over 90% of the ammo I load now is for single-shot rifles, so all I have to worry about is where my rifling begins!

As mentioned above, don't sweat the OAL, most of the time in a factory chamber you MUST exceed the published value to get near the lands. The published values are a guide, but experimentation will give you "your" value and is one of the boons of handloading (you do not have to conform to the common OAL).

On your OAL variance question, how did you measure that? If you measured the OAL to include the bullet tip, especially with lead tip bullets, frequently the tips are deformed enough from the box to give you a slight measuring error. You could try a comparator. I bet your loads are better than you think.

good luck

I have a Model 7 in 7mm Shamu, and it has a lot of freebore, too. My OAL measurement with a Stoney Point OAL tool using 150 gr. Sciroccos was 2.935 to the lands and 2.825 is the max for the magazine. I seat mine at 2.800 and have no problems, even though I would like to get a little closer to the lands.



Bill

Thanks guys. Yes, I was using lead tip bullets. I have started with the minimum load. I plan to find the best oal for my rifle first then, gradually increase the charge to find what works best.

I've started with Nosler's Partition in 180. If I change bullets can I use the same oal for my rifle or will it shoot them differently?

Back to the measuring consistency: I loaded three cartridges without adjusting the die. I measured the OAL for those three rounds: 2.830, 2.829, and 2.835 ???? Should bullets make that much difference?

Finally, the rounds all cycled through my action just fine.

HAVE to measure with the stoney point bullet comparator. If not, you are in for a lot of headaches, I know I was. BULLETS CHANGE FROM LOT TO LOT, make to make. The distance from the OGIVE to the lands is what you are concerned about, NOT OAL, thus you have to use the bullet comparator. When you find the sweat spot with the comparator, you have it made and you can use the same measurement using the bullet comparator for the rest of the bullets unless you decide to be a longrange guy and go VLD.

Just as importantly: DON'T change OAL until you have a sweat powder charge, and start the ogive .005" off the lands for all loads to begin with (best place to start in my opinion). AFTER you find a good powder charge, then change seating depth .005" at a time.

I must agree with Shilen30. Find the best powder charge first, then fool with the less-significant variables afterward, IF the optimum powder-charge load still needs tweaking! Mine usually don't. But I am not looking for bench-rest competitive accuracy, either.

And, of course, as he said, it is the shape of the ogive of any particular make and weight of bullet that determines how much of it can stick out of the case before it starts hitting the lands.

I don't think the OAL of your finished rounds should vary as much as yours seem to, BUT I have never done an extensive check on mine to know if I have the same variation in OAL with my reloads. I believe I will check the next batch to see what results I get.

The variation in O.A.L. that you have is pretty typical. The bullet length from ogive to tip can vary .010 in some cases. I am not sure that I understand the gentleman that talks of changing bullets, but if he is saying that the length, base to ogive stays the same, he is mistaken. It seems as though it should be the same, but it varies quite a bit. Try it with a couple of different bullets, and check it out yourself. As far as seating depth being a less significant variable, the saeting depth can and very often does have a more significant effect on accuracy then any other variable. Bob

This is good stuff guys. I'll order the comparator from Stoney Point. What role does the variation in cases play in this? For example, say I get my die set and it spits out a perfect cartridge. If the next case is 0.005 longer than the previous one and given the fact that we know variances exist with the bullet, will I have to adjust the die for each bullet?

It feels like I'm getting in over my head for a newbie. I measured some factory rounds last night and they are all over the place.

Varying length in cases has two effects, one, neck tension can be slightly different which can affect accuracy, and, two, you have to concern yourself that it doesn't exceed specified length for your chamber. These variances don't have ANY effect on the seating depth of the bullet and the variance from the lands, unless you are crimping your bullets. The variance is a function of your seating die and the shape of the ogives. The ogives vary somewhat in hunting bullets and that introduces variances into the distance from the lands. Also the shape of your seating button in your die will affect this. If you want to go to the Nth degree on this, you must adjust each bullet after seating. Seat the bullets a tad long, then fiddle with the seating stem. If the variances on the bullet are no more than .003"-.004" you'll probably not detect any difference in accuracy. When the get up to .010", or more, then you will see it on paper if you are working close to the lands. This can happen with soft nose (lead) tips that deform in packaging.



I've occasionally tried to adjust the ogive of each bullet. I use micrometer competition seaters. I've never been able to see any real difference in the larger cartridges unless the bullets are way off, which happens occasionally. Don't sweat it unless you progress to the point you are super-compulsive about "perfection".

The length from ogive to BASE OF BULLET does change, but I stated from ogive to base of CASE. When you have worked up a load for accuracy and have honed in on the "sweat" oal (oal= over all length of ENTIRE cartridge), then this will not change if very little from bullet to bullet, though the length from ogive to base of bullet will change. Keep the same OAL after finding the sweat spot. Before finding the sweat spot (or to find the sweat spot), vary oal .005" at a time until you find the magic distance, and yes there is such a thing.

If you have the same make and product number of bullets that vary more then .001 from ogive to base it is time to try some other bullets, they cartainly shouldn't. What I was trying to say and may not have been as clear as it could have been, is that you determine a seating depth of one bullet that works for you, and you decide to use another bullet it will more then likely need to be remeasured to get the same results. A new O.A.L. with a comparater must be determined with each different bullet.

Makes sence. Believe it or not, the 200 grain sierra matchkings I shoot out of my 300WM vary as much as .004" from ogive to base comparing one lot I have compared to the rest I have ever purchased, but when I shoot them with the same load to the same OAL (measured with the bullet comparator), they are pretty much the same. I have also had this problem with some hornady and nosler bullets I bought (so I guess with all the brands I buy at one time or another), but I don't consider it a real problem. Again, that is from lot to lot. With my sierras, my bullets do not vary more than .001" from ogive to base in the same lot which is better than any other bullet I have loaded.



I will admit though your method will get you very close (certainly within .004", usually less).

I am sorry that I did not say bullets of the same lot. Certainly bullets from different lots can vary quite a bit, Usually from a high volumn maker. I am using bullets from a custom maker that vary VERY little even from lot to lot, and quite a bit lighter 30S then you are using. It would take a lot for me to change bullet maker now.

I guess I don't understand the problem myself. If you use the same kind of brass and trim it after you resize it to the same length or even different brands of brass if it's the same length and use the same kind of bullets you should be able to turn out the ammo of the same length just about everytime after your initial adjustments like factory ammo.



500Mag

There are at least two problems you have in turning out the same length cartridges. The first is the slight differences in the shape of the ogive. The second is the shape of the seater button that contacts the ogive, or the tip, of each bullet as it's seated. If the button makes consistent contact with the different bullets on the ogive, you have a good chance of reasonably consistent cartridge base-to-ogive length, providing the ogives are all very consistent. They are close but not always exact. This will cause a variance. The seater button shape is probably the most critical.

If the seater button contacts the meplat, or tip, you are subject to the the variances in length from the base of the ogive (which makes initial contact with the lands.) These vary significantly, particularly in the soft nosed bullets. The length of the brass has very little to do with the relationship of the bullet and its contact with the seater button and the lands.