I have been loading a flat nosed 9MM cast bullet using the flat nose bullet seating stem. Then I loaded some FMJ 115 grain bullets without changing the seating stem. This produced a flat nose on the otherwise round nose FMJ's. Seating resistance wasn't noticeably increased.

Has anyone else experienced this?

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Go to Hell Ole Miss

I am not sure how the shape was changed on FMJ bullets? That should have taken a great deal of pressure and would have deep seated the bullets.

They will round out as they go down the barrel!!

I totally agree with Max above me however,...can you post a picture for us?

Randy

I only have a SWC stem for my 38/357 dies and have been too lazy to get the correct one for RN. I loaded 75rpunds of 38 RN polymer coated this week and had a small bit of flattening on the nose. I’ve done this before and never had any issues. It flattens roughly 2mm on the tip. I’ll get around to getting the correct one sometime.

I have seating stems for wadcutter, semi-wadcutter, round-nose, and a few others in several different calibers that I load regularly. After tens of thousands of rounds of ammunition produced about the only thing I have yet to see is a seating stem that is perfect for any application.

Round-nose seating stem may apply some compression to an exposed lead hollow-point bullet tip. Semi-wadcutter stem may impress a slight, but noticeable, ring on otherwise perfect bullets. Wadcutter stem will always result in a flattened spot on the nose of any bullet seated.

Same issues with the Lyman and RCBS lubricator-sizer machines. Hundreds of "top punch" profiles, some of which may be perfect for one cast bullet, but most of which are "close enough".

With a well-equipped machine shop and a skilled lathe operator we could probably turn out a perfect seating stem for any given bullet. Not having access to such luxuries I have always settled for close enough!

All of my dies for all calibers have one (1) seating stem. Seated all kinds and shapes lead and FMJ. How the OP can flatten a RN bullet seating it is beyond me??
The bullet slides into the case mouth to me it would be impossible??


What kind of seating die is the OP using??

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For office use only

My RCBS dies for .380 had a "TC" seating stem (only one) and when loading RNL (coated) there was a circle being cut around the nose of the bullet. I called RCBS and they tell me the die seating stem was for Truncated Cone bullets, but wasn't marked on the box. They sent me the RN seating, no charge. Once again RCBS comes through as a great company.

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H Richard
SWCA1967 SWHF244

It's OK ...I've done it more times than you can shake a stick at .
The little flat spot that results on the otherwise RN hurts nothing .........
Choot 'Em !
Gary

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Certified Cajun
NRA Member

I don't think that I've ever changed the seating stems in any of the many cals that I load for.... Probably still using RN stem for wadcutters in 38Spl.... or vice versa... Same with .45acps of colts.... As long as i change the depth settings for whatever I;m loading, I've been happy with my results.
J

You didn't mention if you adjusted for O.A.L. when switching to the FMJ projectile. Depending on the powder and charge, you could have pressure issues if you seated too deep. There's not much volume in that 9mm case.

With 9mm loads.........

there is nothing wrong with a round nose bullet stem in the die
for all your loading.

I change out my single stage to flat when I do 38 WC ammo.

I don't recall ever having changed a bullet seating stem from semi wad cutter in over 50 years of reloading.

If all else fails, put a pea-size ball of aluminum foil into a SWC seating die. With the first round you will get a purpose-built seating die for that particular bullet.
If you need to seat a different bullet, just dig out the aluminum and repeat the process.

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and what his trumpet saith

I have deluxe die sets that have different seaters, in pistol calibers.

Just loaded some 130gr plated 9mm bullets originally designed for 38 Super: used the flat seating stem from the Hornady dies and it put a nice little flat point (about an 8th of an inch in diameter) on the nose. This actually would lead to a little longer (than measured) effective OAL...?

In the past I have certainly noticed rings on plated bullets when using the other (RN/HP?) seating stems, most often on 9mm. I think it has more to do with the thickness of the plating. Hardly ever on the Berrys HBFN-TP or HBRN-HP versions.

Cheers!

95% of the time, any seater stem seems to work OK on multiple bullet nose types.
It's that other 5% that some folks just don't notice.

Depending on the diameter of the bullet and the diameter of the case mouth, bullets can be hard to seat. When that happens, deformed bullet tips can occur.
Sometiimes even a bell mouth can still get shaving from diameter mismatch as well. It happens.

When I am doing setup with new components, I always try to just barely start to seat; and then stop and check for alignment. The driving bands should be concentric with the case mouth. If they're not, you may have a stem mismatch issue. Shaving may start to occur as well.


stay safe,
and good loading,
Prescut

As mentioned for the 9mm loads just let them rip.........

You might try a little more belling of the case mouth to see if that might minimize the flat dimple on the FMJ style bullet but
for 50 yard work, I don't think it will hurt any thing.

Of course my pistols are not "Super Duper" custom, lazer accurate weapons that can tell the difference of a bullet being "Dinged" !!

Carry on.

I found out about the flat spot on a 121gr. Round nose cast bullet while sizing and lubing! Makes a great flat spot on the nose with a flat top seating plug.
Semper paratus

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NRA Life Member
CPO

I've shot some pretty ugly and messed up bullets out of my guns over the years and to be honest, I saw little difference in performance.