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Seating depth, COL, Tip Length

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So here's a question for everyone. When loading up some 223s I noticed today that there is quite a difference in the tip bullet length. I measured a good 20 of them and the smallest was 0.898" with the largest of 0.912". Obviously this is going to make quite the difference in overall length since that's a 0.014" spread across the 20 or so pieces that I measured. So here's the question. In this situation would you still load to a COL of 2.260? My general rule when making more for plinking is +/- 0.005 for a tolerance. Or would you set the COL for a bullet that measures the max of 0.912" and then let the smaller ones drift down towards a COL of 2.246". This would be my initial thoughts.

Thanks in advance
James
 
That's a tough question, here's my answer:

Sort the bullets into groups no less that 0.003" base to tip, ie bullet length. If you start having too many groups, either expand the .003 or buy better (more expensive) bullets. Load all of them to 2.260 and shoot them as groups. The point being to keep the "like" bullets together. Obviously you can't just dump them into the same bucket after doing all that hard work.

Now, if you really want to find out more about the bullets, try measuring base to ogive in addition to base to tip. Not saying base to tip isn't important, it's just a measurement with considerably more variance.

In any event, I would never base seating depth decisions on bullet OAL unless I was so close to magazine length I had to do it.
 
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If it's a magazine fed gun, find the longest one and use it for your max OAL.

However, when seating the bullets, go off of the ogive for your reading. Set the depth based on clearance for the tip of the bullet (over all length of the cartridge) to fit into the mag. If clearance is not a concern (plenty of room for the bullet to clear) then don't worry about it and just load based on the ogive reading and how much jump you want the bullet to have before it engages the rifling.
 
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Lots of good advice here. Sierras can and will vary around .020 with the 69gr & 77 HPBT's

As mentioned before, set your seating die up for the longest bullet you can find and load them up. Black Hills 77 grain ammo averages around 2.245.

That wild tip variation means absolutely nothing to accuracy.

Get a Redding Competition Seating Die at Brownells. You can find the number on it that works and write it down. Then go back on a different day and dial it right in.

Try not to make too many "general rules" until you get all this stuff sorted out. There is a lot to learn.

Sierra bullets can handle lots of "jump".

Don't fret about pressure being different because you seated the bullet farther in and all this stuff. A good long think on that will reveal that some of your bullets will be at 2.260 and some will be at 2.240. Pressure will be identical because your seating stem pushes the bullet down from a point on the ogive. Not the tip.....

If it were seating the bullets by pushing on the tip... Now that would push some farther down than others and of course would be a different story.

I have a Redding T7 press and normally don't remove any dies. If you are constantly messing with your dies just measure a pile of the bullet you are loading, find the longest ones, then create 1 dummy round at 2.255 - 2.260. (save the rest in a bag)

The next time you set your die up you can turn the seating stem down by hand with the dummy round up in the die. That will get you close. Then grab one of the longer ones you saved just for this and seat it for 2.255 - 2.260 and go to town.

Buy a RCBS collet type bullet puller.
 
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C
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Thanks guys. That's kinda what I was thinking as well. As for the RCBS bullet collet puller already have one with matching collects for all rounds I load. My 308 loads with nosler RDFs are down to about 0.5moa. Actually quite impressed with that load. It's just working up the SS109s now. I have the 55gr fmjs pretty well dialed in. Probably end up trying the RDFs in 223 since the 308 likes them so well.

Thanks
James
 

bsa1917hunter

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So here's a question for everyone. When loading up some 223s I noticed today that there is quite a difference in the tip bullet length. I measured a good 20 of them and the smallest was 0.898" with the largest of 0.912". Obviously this is going to make quite the difference in overall length since that's a 0.014" spread across the 20 or so pieces that I measured. So here's the question. In this situation would you still load to a COL of 2.260? My general rule when making more for plinking is +/- 0.005 for a tolerance. Or would you set the COL for a bullet that measures the max of 0.912" and then let the smaller ones drift down towards a COL of 2.246". This would be my initial thoughts.

Thanks in advance
James
if you load for precision you don't do C.O.A.L., you'll load from the ogive length, not the tip.
Yeah, and you'll know exactly how far from the lands you are as well. From the sounds of it, the OP wants to keep them right at AR mag box length. Or I'm assuming so, based on his criteria of "2.260 COL".... For my ar's I do like Dizzy said and find the longest bullet and set the die to that bullet and back off to 2.255" for my AR's. Generally I only use good bullets that are very consistent in bullet length. Such pills as the sierra match bullets, sierra 77TMK, 69 mk, and the hornady eld match bullets. After I run these through the seater, they all measure within .002" of each other and are well within the constraints of the magazine length..... This stuff isn't hard and you can still load good accurate ammo by backing off magazine length by .005". Here's how my AR's shoot with said bullets:

223 rem with 69gr sierra mk
ctFQKsq.jpg

I generally don't post 3 or 5 shot groups here, but what the hay:
lFEsNjg.jpg

Same seating depth (see target), but different rifle:
vkI6iIY.jpg

73gr Bullet seated at 2.255" OAL
3yTt2jU.jpg

My new barrel on one of my AR's, with a new load using the 77TMK. 2.255" OAL...:
4TneMTK.jpg
BWTKeED.jpg

That's how I do it anyway....;)
 
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bsa1917hunter

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If it's a magazine fed gun, find the longest one and use it for your max OAL.

However, when seating the bullets, go off of the ogive for your reading. Set the depth based on clearance for the tip of the bullet (over all length of the cartridge) to fit into the mag. If clearance is not a concern (plenty of room for the bullet to clear) then don't worry about it and just load based on the ogive reading and how much jump you want the bullet to have before it engages the rifling.
Perfect answer buddy...
 

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