OAL help

[SPGuy]

So I decided to find my lands and found this way, http://www.larrywillis.com/OAL.html considered the poor mans gauge. It worked consistently with remington Core-lokt in 150gr, but when I tried the speers boat tails in 165gr they did not seem to contact them. I even had the bullet just lightly hanging in the brass and it still easily seated in the chamber and extracted. I am using a remington tactical in a 308. Am I missing something?

[BenHa]

The oal for my rem aac-sd was pretty long ..... something along the line of 2.930

[Bill Steele]

Bullets have different ogive shapes as well as OAL (the bullet that is), so different seating depths will be needed to get them to the lands.

The first thing I do with a new bullet is determine where I need to seat it for zero jump (I use a comparator to measure this dimension to get as consistent result as possible). I then write that dimension on the box for quick reference later.

Good luck.

PS -A rule of thumb I use with stock 700 barrels is an OAL about .150" longer than magazine length (call it 2.950") will get most bullets pretty close to the lands. Obviously each bullet is different, but the throats are pretty long on factory stock barrels.

[mark501w]

Like bill sez my 700's throat is longer than the magazine. I crowd the length of the length of magazine with a dummy round & save it to set the bullet seater.

[SPGuy]

Thanks for the help guys, those who have a remington what is your typical OAL.

[mark501w]

168gr Sierra international loaded to max magazine length @ 2.938".

[Bill Steele]

With my favorite BDL magazined 700 in 308, my maximum OAL is like 2.810" if I want to feed from the magazine (hunting). For paper punching, I single feed to get the optimal jump and the OAL ranges in the 2.930" to 2.960" depending on the bullets I am loading.

How much jump that is optimal depends on the bullets you are loading, the gun you are loading for, many factors. I treat jump as just another load factor and it takes some experimenting with a given load to get an ideal specification. If you change a component, you will want to rework the load, at least if you are trying to squeeze the ultimate POI consistency out of things.

Lately I have been loading some bulk 150gr FMJ/BT's and have developed a load that will shoot .2 MOA at less than Palma ranges (with sorted bullets). These bullets have a pretty long jump when seated at max length, owing to their shape, still shoot great.

Good luck, have fun.

[SPGuy]

I just want to say thank you all very much for the help...Bill last night I played around a bit and found my magazine will hold up to a 2.878 OAL. Would you suggest I start with that length or work from a shorter length up to that? This is going to be an all around gun for me which means taking it hunting so having use of the magazine is a bonus to me.

[mark501w]

My magazine must be a little longer than yous guyz.

[Whiterabbit]

if you want to really know the land distance, stick a bullet down the chamber and hold it against the lands with a dowel. stick a cleaning rod down the bore and mark it.

Chamber a dummy round and mark the cleaning rod again (must be same bullet).

Add dummy round OAL to the distance between marks on the cleaning rod and you have max OAL.

I find often that a good jump to the lands helps accuracy. Second best is right close (I mean REALLY close). Between the two never seems to do so well.

I usually seat deep. Usually.

[Bill Steele]

I just want to say thank you all very much for the help...Bill last night I played around a bit and found my magazine will hold up to a 2.878 OAL. Would you suggest I start with that length or work from a shorter length up to that? This is going to be an all around gun for me which means taking it hunting so having use of the magazine is a bonus to me.

At 2.878" you are still jumping a fair amount (probably in the .050"-.080" for a 168gr bullet), so it probably doesn't matter where you start. I have found a couple of the bullets I favor these days (those would be the one's I find in stock ), a jump in the .050" area seems to work best (AMAX 168gr, SMK 168gr, etc.). As I mentioned those bulk 150gr FMJ/BT bulk bullets (sorted of course) I have been loading for fun lately jump well over .100" and I can get them to shoot as good as anything twice the price at shorter ranges and on a good day.

In the grand scheme of thing (especially for hunting loads), you want to find an accuarcy node on the higher end of the velocity spectrum for the bullet weight and then maybe fool around with optimizing the jump (which is a second order effect anyway).

When hunting, feed reliability is paramount and OAL should be where that is not in question (not that you will ever need a second shot!). If you are not crimping your hunting rounds (most people don't seem to these days), you might want to consider giving yourself a little buffer length wise just in case you get a little walking out of the rounds in the magazine under recoil. What happens in my guns is if the OAL is too long I will get a feed jam.

As WR mentioned above, jump is not always a bad thing. You will read a lot of people swear up and down that seating to (or even into) the lands is the only way to get maximim consistency, this has not been my experience.

The good news is you can experiment and find what really works for you, your custom ammo and your rifle.

Have fun, good luck.

[JagerDog]

Beware, that if you ever hunt with copper, stick to the bullet mfg's data or pressure can soar.

We used to seat a flat based bullet backwards to determine land distance.

[Bill Steele]

My magazine must be a little longer than yous guyz.

Thats a good thing to my mind. I have a few 4064 loads with heavier bullets that I really can't get to seat to a 2.810" OAL (my max magazine length in my favorite rifle), just too compressed. One of these days I may take a dremel to my magazine metal and see if I can make things a little more roomy.

[BenHa]

My magazine must be a little longer than yous guyz.

My longer loads fits in my mag but doens't clear the feeding ramp

[Whiterabbit]

heh, I've heard of folks loading so long that it doesn't fit the ejection port (even shoehorning) and they have to pull the bolt to get the round in there

Obviously these aren't hunting loads anyways, but some folks like to load LONG!