Difficulty Seating Flat Based Bullets

[Phil3]

Every few rounds, I encounter difficulty seating a bullet. That is, the initial start of bullet seating shows higher than normal resistance, and then it suddenly gets much easier, feeling like other bullets that go in easily with a consistent resistance. The bullets are flat based and wonder if they are catching on the case neck edge when first started. I feel I have deburred the inside of the case neck adequately, but maybe not. What might be happening. The components and tools are:

Forster Co-Ax press
Forster micrometer type bullet seater
Forster full length resizing die
Winchester brass (both new and fired, and always deburred)
Sierra 52 and 53 grain flat based bullet

Thanks.

Phil

 

[mac86951]

What neck chamfer angle tool are you using?

45° or a vld type tool 38°?

What is neck size before seating and after seating is your neck tension consistent?
Do you turn your case necks?
What is neck wall variation?

-Mac

 

[dkhunt14]

Do you have the expander ball in die? If it is I believe you are not chamfering hard enough. Is it shaving off any copper from the bullet? Matt

 

[JohnKielly]

Is it shaving off any copper from the bullet?

I had that issue with an early K & M VLD tool, one without the pin to center it through the flash hole.

I bought a Wilson VLD tool & I know that I get an even chamfer that has all the dags turned off.

 

[LHSmith]

Try polishing the chamfer with 0000 steel wool or a scotchbrite pad. If using steel wool make sure you blow out any residue from inside the case.

 

[mac86951]

All that, and all add I've had mixed results with cheap brass that had lopsided neck thicknesses.

 

[dkhunt14]

I have seen Winchester brass be harder then others. Maybe that is why. Matt

 

[gotcha]

Flat based bullets can cause the problems you're encountering if you have neck tension higher than .0015" ....... Otherwise, most all the advise is excellent.

 

[Danattherock]

Buy boat tail projectiles. Seriously. Just change the pill. If loading a lot at any rate. I bought a 6,000 count box of Hornady 55 gr from Midsouth Shooters for a plinking load on my Dillon 550. After about a thousand rounds, it occurred to me (I'm slow) to buy boat tails next time. Which I did, as the same basic bullet from Hornady is available in flat base or boat tail. Drastically faster for me to load on Dillon 550 with the boat tails.

Dan

 

[Phil3]

Thanks to all for the replies. The neck tension may be too high for the flat based bullets.

I did not measure an unloaded case vs the same case with a bullet, because well, time and circumstances did not permit. But, what I did do should suffice. I figured each case will have the same inside neck diameter given the expander ball went through every case. I used my lathe to make a short aluminum rod that was a very exact slip fit into the neck of a resized case that was sized using a FL die. The rod measured .2222" The inside of the case would be very, very close to that, given the precise fit of the rod into the neck. The Sierra bullet measured ..2242". That leaves a neck tension of .002" which I think can be high enough to cause problems with seating flat based bullets. ???

In answer to other questions.

The neck chamfer tool is a standard 45 degree type with no guide to center it in the neck. Probably should get one that centers off the flash hole.
I do not turn the necks.
Neck wall thickness variation on the Winchester brass is certainly there. I have seen it vary .002" on one case, and more than that from one case to the next.
The expander ball is being used.

How does one reduce neck tension? I am not sure sure I want to do that given this is an AR-15 semi-auto, which rather manhandles the cartridge. Perhaps a better chamfering job is the best approach. ??? Recommended top quality chamfering tool?

Thank you.

Phil

 

[Phil3]

Buy boat tail projectiles. Seriously. Just change the pill. If loading a lot at any rate. I bought a 6,000 count box of Hornady 55 gr from Midsouth Shooters for a plinking load on my Dillon 550. After about a thousand rounds, it occurred to me (I'm slow) to buy boat tails next time. Which I did, as the same basic bullet from Hornady is available in flat base or boat tail. Drastically faster for me to load on Dillon 550 with the boat tails.

Dan

From what I have read, flat based bullets do best in short range shooting. My range is 100 yards. My twist rate is 1:9 and while that theoretically could shoot 69 grain boat tails, the gun does not seem to care much for those. Maybe I have yet to find the right load... Will keep trying.

I don't do mass reloading, using a single stage press. The more tedious flat based bullets don't bother me much, but yes, boat tails would be easier.

Phil

 

[savagedasher]

I would recommend you check how the seating dies should be set up. It could be your die set up is wrong. Larry

 

[Webster]

Every few rounds, I encounter difficulty seating a bullet. That is, the initial start of bullet seating shows higher than normal resistance, and then it suddenly gets much easier, feeling like other bullets that go in easily with a consistent resistance. The bullets are flat based and wonder if they are catching on the case neck edge when first started. I feel I have deburred the inside of the case neck adequately, but maybe not. What might be happening. The components and tools are:

Forster Co-Ax press
Forster micrometer type bullet seater
Forster full length resizing die
Winchester brass (both new and fired, and always deburred)
Sierra 52 and 53 grain flat based bullet

Thanks.

Phil

Never had a problem seating FB bullets. I very lightly chamfer each case with every reload, not just one time. FB bullets have a decent radius at the base. I don't know if the die straightens out a bullet or how well it it's straightened when hand placing it on top of the case. Can someone comment on if the seating die holds the bullet very straight before it's pushed in? It would be interesting to just seat a bullet maybe 0.050" into the case and remove it from the die and check run out.

 

[divingin]

Never had a problem seating FB bullets. I very lightly chamfer each case with every reload, not just one time. FB bullets have a decent radius at the base. I don't know if the die straightens out a bullet or how well it it's straightened when hand placing it on top of the case. Can someone comment on if the seating die holds the bullet very straight before it's pushed in? It would be interesting to just seat a bullet maybe 0.050" into the case and remove it from the die and check run out.

Most seaters have a holt that the tip of the bullet goes into; that, in theory, should get the tip of the bullet in line with the case. Assuming the base of the bullet doesn't deform the case mouth as it starts to seat, you won't be too far off.

Off-topic: You could have posted a new thread, rather than resurrect a 6 year old one.

 

[Webster]

Most seaters have a holt that the tip of the bullet goes into; that, in theory, should get the tip of the bullet in line with the case. Assuming the base of the bullet doesn't deform the case mouth as it starts to seat, you won't be too far off.

Off-topic: You could have posted a new thread, rather than resurrect a 6 year old one.

Guilty. Once I asked the moderator if they would clean up the website by deleting any post over 3 YO. He said to much good stuff would be deleted. I still think it's a good idea. There are post over 10 YO on the website. Much of it repeating the same questions. There are over 360,000 post under reloading.

 

[itchyTF]

How about instead of deleting to put all "old" threads in a separate forum?

 

[PopCharlie]

I just had a similar issue with Bib 95 gr Flat base bullets in my 6br. The rifle has a .266 neck, so I turn neck to .010. I was using a .261 bushing and a .241 pin gauge to size and set the tension. I was getting very heavy seating force required to seat these bullets. 90 gr Berger BT seated normally. Today I switched to a .263 bushing and a .2425 pin gauge. Problem solved.
I use a K&M arbor press with a force pack and Wilson seating die. The Bib bullets have .2437 pressure ring.
PopCharlie

 

[Murray Brook]

Guilty. Once I asked the moderator if they would clean up the website by deleting any post over 3 YO. He said to much good stuff would be deleted. I still think it's a good idea. There are post over 10 YO on the website. Much of it repeating the same questions. There are over 360,000 post under reloading.

What you have posted in some regards is most certainly true. But 2 years ago I had my first 6mm BR built. I needed a lot of info so I could get things right and rather than start new topics I used the search function to look into older threads , some dating back as far as 10-12 yrs. The information I gathered was invaluable in my build. Reading senior members takes on twist rate, free bore, barrel length , powder choice, bullet type etc was priceless and it did result in a very accurate build. I guess I kind of agree with the moderators.

 

[Texas10]

Are you annealing your brass? How a bullet seats into a case that's been fired once is very different than seating a bullet into a case that's been fired 12 times. If you don't keep close track of the cycles on your cases and keep them segregated, you can't expect consistency in loading pressure.

Flat based bullets have a pressure ring on the back end, it's the first part of the bullet that enters the case and ANY inconsistency in the case mouth chamfer, neck hardness or cleanliness will cause inconsistent seating pressure.

Anneal, clean, chamfer if you want consistent shot placement. There are no shortcuts!

 

[AWS]

I've gone to Hornady seaters with the sliding sleeve, bullets are lined up straight right from the start, even loading little 33gr 224 Flatbase, they never get cocked in the seater. I also trim and chamfer every loading,.