Need help with bullet seating

[longbowelk]

I am using an old RCBS single stage press. I am using RCBS dies and this is for a 7mm08. Been loading off and on 40 years. Not an expert but self taught and still learning thanks to this site. I used to go by loading books etc and seat my bullets by COAL. After being on this site and really learning about bullet seating depth using the base to ogive (bto) measurement using a Hornady tool and dial caliper I am realizing how to really seat the bullet for better accuracy etc. Here is problem: I loaded about 50 once fired Hornady brass after trimming to 2.025. I used the 140 gr Nosler AB. I set the BTO to 2.285. After doing a few and measuring I went ahead and finished the rest.. After shooting a 3 and 5 round group the grouping was over 1". I pulled out the ammo and started remeasuring the BTO. To my surprise I had a range of 2.285 to 2.291.
Is there something I am doing wrong or is the die messed up? Any suggestions as this is totally not satisfactory.
Thanks for any and all help.

 

[RMulhern]

If you're using a dense charge the base of the bullet may be hitting the powder charge and easing slightly upward as you withdraw pressure from the seating die! You can solve that problem by charging the case using a droptube!!

 

[Mikecr]

After doing a few and measuring I went ahead and finished the rest..

So taking shortcuts doesn't work out for you? They don't work out for me either..

 

[longbowelk]

Im not sure what you mean by taking short cuts. Unless you are referring to not measuring each one. I figured if the first 2 were correct that it was set and the rest would be good.
As far as the powder being compressed I do not believe it is. 46 gr of IMR4350 doesn't appear to be compressed. I'm thinking that I am still under max powder.
I guess I should take the die apart and examine it.

 

[rcoody]

Could be that bullet not being a match bullet has a lot.of.variations. try sorting a box with the bullet.comparator

Could be that old RCBS press has worn linkages

Could be your seater stem

Could be if you are going for.precision that you need to buy a benchrest seater die

I have.found the best seater die.for.me is the Wilson in line seater

 

[Mikecr]

I figured if the first 2 were correct that it was set and the rest would be good.

So what did you learn about that?
Do you think now that all your ammo will be the same and correct -without verifying all your ammo is the same and correct?
Do you measure every shoulder bump and every powder charge?

 

[Predator 22]

My guess would be that your die is seating off of the tip of the bullet. I would take the seating stem out of the die and paint the tip of a bullet with a magic marker and rotate it in the stem and see where the marker comes off. If it is the tip try a different seating die. Hope this. Helps

 

[Kansaswoodguy]

My guess would be that your die is seating off of the tip of the bullet. I would take the seating stem out of the die and paint the tip of a bullet with a magic marker and rotate it in the stem and see where the marker comes off. If it is the tip try a different seating die. Hope this. Helps

^^^^^^ this

 

[cornchuck]

I think what you seeing is that the ogive of your bullets are not exactly the same. Which can be common. What I have started doing is seat the all my of my bullets to about .005 longer than I want them to be. Then I go back push them down farther one by one while measuring them as I go.

Jason

 

[TonyQ]

You need to measure each one. Also don't forget to sort your bullets by ogive. I sort in .001 but some sort by .002 lots. Use these dies it will make your life easier. Redding Type S Match Bushing 2-Die Set 7mm-08 Remington

 

[longbowelk]

I did measure the Ogive of 5 bullets from the box of Nosler Accubond 140s, and same with Sierra 140 SPBT both in 7mm. They all were precise as far as my dial caliper.
So, I will eliminate that for now.
I don't think the die is worn out as it has probably only loaded 200 rounds.
I will look into Predator 22 advice on checking the stem and bullet tip.
If that doesn't work out I will consider the competition or match bullet seater.
Whatever method I come up with I will try to monitor more frequently the final cartridge ogive measurements.

Thanks for all the information. I believe I can resolve the problem with this information.

 

[rcoody]

I did measure the Ogive of 5 bullets from the box of Nosler Accubond 140s, and same with Sierra 140 SPBT both in 7mm. They all were precise as far as my dial caliper.
So, I will eliminate that for now.
I don't think the die is worn out as it has probably only loaded 200 rounds.
I will look into Predator 22 advice on checking the stem and bullet tip.
If that doesn't work out I will consider the competition or match bullet seater.
Whatever method I come up with I will try to monitor more frequently the final cartridge ogive measurements.

Thanks for all the information. I believe I can resolve the problem with this information.

Think about this.the seating stem is not catching the bullet at the ogive. It should be catching.the bullet somewhere near the tip. If that part of your bullet is not consistent then seating depth can't be. Take the stem out and check and see how it fits on a dozen or so bullets.

Frankly a variation.of .006 is not going to make any difference in your.groups unless maybe you are 1000 yrd competition shooter

 

[philipbrousseau]

Rcoody number one. my experience measuring nosler ballistic tip bullets is there is alot of variation among the bullets in a box.

 

[rcoody]

Rcoody number one. my experience measuring nosler ballistic tip bullets is there is alot of variation among the bullets in a box.

That has been my suspicion since I first saw this thread