Did my die or Jwords do this?

[Tripplebeards]

I tried to load up 180 grain hot cores in some brand new RP 35 whelen brass today. I FL sized the brass like always with a brand new set of RCBS dies. I then went through the process of trimming, chamfering, deburring, primed, fillEd with powder, And tried to seat my Speer .358” hot cores. Here’s what happened...

https://i.imgur.com/I6zq0Lt.jpg


I wrecked two cases and then sent all the rest of cases back through My FL sizer again figuring I didn’t adjust my die properly. I seated the first two bullets smoothly...then the next one crunched the case again. After I wrecked to two more cases. I stopped with any resistance and started grabbing bullets one after another auto try and found out that some would seat smoothly. I measured the ones that wouldn’t. Most that wrecked my case necks and wouldn’t seat were .3595” to .360.5”. I was blaming it on my die set at first but I’m guessing it’s my to big of diameter bullets? I called speer and they are having UPS pick them up for inspection and replacement IF they measure out to large on diameter. I might cover all my bases and all RCBS or see if they can send a replacement neck sizer insert? Any other ideas what might have caused this? I swear I went through this same issue with the same bullet years ago loading in my 35 Remington as well. I thought I sent the bullets into speer and they replaced them as well. So I believe it’s the second time around with the.358 hot core. I wonder if the lead is expanding from sitting around for 15 years or they just were not sized correctly right off the bat. The Speer rep said he hadn’t seen issues like this in years. I told him they were Probably 12/15 year old boxes I bought new and I just opened the first one and the other one I still sealed he didn’t seem to surprised. I wish I would have quit after I wrecked the first new case as the RP 35 Whelen cases are as common as unicorns.

[tomme boy]

Needs more inside chamfer or bell the mouth

[Tripplebeards]

I agree belling the mouth would definitely work like I do with cast but I wasn’t aware I had to do that with J words? After the first go around years ago with my 35 Remingtons they have been seating just fine with this bullet. When I felt resistance the bullet started expensive but got stuck in the first 1/16” of the neck. Any more pressure and the case distorts.

[Winger Ed.]

I'd bevel inside the case mouth first.

The bullets may not have enough bevel/taper to go in without 'snagging' the top of the neck.

If the bullet dia. is all within spec. and the neck isn't too thick, the expander ball isn't too small from wear-
give the cases a little bump with a 'M' die.

[Tripplebeards]

When I measured the Problem bullets were .0015 to .002” over Speers spec according to their rep. I’m going to see if RCBS will send a replacement expander ball. The dies are brand new. I’m paranoid now the ball might be out of spec as well?

[BigAlofPa.]

I had to get a larger expander for my Mosin. The stock one i was shaving boolets when seating them. I had crushed some cases on the shoulder resizing when i 1st started rifle. To much lube was the cause.

[TheDoctor]

I've had that happen when the case hits the crimp shoulder before the bullet is fully seated. A seating only die, no issues. A seating/crimping die, die adjustment will get ya.

[Bazoo]

Personally, I use an M die with jacketed bullets that are flat based. I never got the hang of balancing a bullet on a case with no bell.

[tomme boy]

Factory ammo is belled to speed production. If you have an extra station in a progressive it will speed up your production too as you do not need to chamfer the inside. Been doing this for years for my 223 range ammo with jacketed. Your seating die will remove the bell when you seat a bullet. Or run a Lee crimp die to do it. done it both ways

[JSnover]

I'd bevel inside the case mouth first.

The bullets may not have enough bevel/taper to go in without 'snagging' the top of the neck.

If the bullet dia. is all within spec. and the neck isn't too thick, the expander ball isn't too small from wear-
give the cases a little bump with a 'M' die.


Bingo! Too many variables. I've found a lot of flat-base bullets that have enough of a radius to enter the case without prepping the mouth... until I hit one that doesn't, for any of the above reasons.

[Half Dog]

I had a similar issue that was caused by the seating stem not fitting the profile of the bullet. It was seating the bullet at a slight angle.

[jcren]

I just loaded a bunch of 35 remington with Hot Cores and had issues with them wanting to hang on the case mouth. Just used the lee universat to bell them a bit and it worked fine.

[Tripplebeards]

I just loaded a bunch of 35 remington with Hot Cores and had issues with them wanting to hang on the case mouth. Just used the lee universat to bell them a bit and it worked fine.


My cases cut even ring around the hot core bullet bases I removed that would not seat. These were on the ones I could feel pressure while lowering my press handle and wouldn’t seat. I stopped the process before they would have crushed the necks. I inspected them to make sure they were all started evenly as well. Since Speer is good enough to have my send them back in I’ll get them inspected just to be safe since some were measuring as big as 360.5”. If I have the same issue I’ll start being my case. I remember it wasn’t my 35 Remingtons that had this issue but another caliber and it wasn’t from setting my die up properly. That’s why I went through and resized my brass again. All components are brand new...RP brass, RCBS dies, and Speer bullets. Speer told me their bullets should be .359” at the largest and I had a lot at .3595” to .360.5”. IMO they still should slide right into my brass. I’m wondering if my RCBS neck sizer ball is to blame? I’ll get a replacement ball from RCBS and if it happens after trying and new ball and bullets I’ll start belling the necks with my lee universal die like I do with cast.

[Larry Gibson]

Personally, I use an M die with jacketed bullets that are flat based. I never got the hang of balancing a bullet on a case with no bell.

The easiest solution......

[Tripplebeards]

I’ve heard of the M dies but never seen or used one. How do they work?

[BigAlofPa.]

https://www.lymanproducts.com/rifle-neck-expanding-m-dies

[jonp]

I've loaded those bullets in new brass for my Whelen with no problem. I suspect an incorrect set die. I seat and crimp in 2 steps. I'd try doing that.
I also use a Lee Universal mouth expander flaring just enough that the flat base will go into the brass and balance the bullet but no more

[mdi]

A .308" slug is very difficult to insert into a .305" tube without providing an entryway. I flare or use an M die on all my handloads, lead or J...

[Winger Ed.]

I’ve heard of the M dies but never seen or used one. How do they work?

It does the job of the mouth flaring die for straight wall pistol cases.

[mdi]

https://www.lymanproducts.com/rifle-neck-expanding-m-dies Yep, two diameters and second step/diameter also can add flare...

[W.R.Buchanan]

3B" you definitely need to flare your case mouths a little more to accept a bullet with a square base. If the base is square, and the case mouth is square and smaller,,, They won't go together. Period!

You can just get a Lee Flaring Die which is totally adjustable to create any amount of flare you want and they are like $10.

Or you can use Boat Tailed Bullets which will go in the hole.

Randy

[Tripplebeards]

I have lee universal flaring die. I use it exclusively for cast. I’ve never had to flair for J words to seat into bottle neck cartridges in 20 plus years of reloading so this is a new one for me. No issues with the same bullet seating them in 35 Rem RP cases without flairing the necks. I stated above I did have an issue but it was with another caliber and not the 35 Rem. So why do they work without flaring in my 35 REM’s? I’m guessing the new die set’s expander ball is undersized? Either way I’ll be flairing my Whelen cases. A couple of the ones I did get to seat went in very easy and a couple went in with some force for some reason.

[W.R.Buchanan]

3B" If the base is square, and the case mouth is square and smaller,,, They won't go together. Period!

Randy

This is what you are experiencing. With cast not enough flare = lead shaving. Copper doesn't shave as easily and thin brass gives up before it can shave the copper. Hence your destroyed cases.

Or you could put your bullets in a lathe and file a radius on the base of each one. I think flaring is easier.

Randy

[Tripplebeards]

I must have some hard casings because I did shave some of the brass off the bullets as well.

[bedbugbilly]

I use a Lyman M die for both cast and jacketed.

I started with a Lee universal expanding flare die as shown above and it worked O.K. but finally graduated to using M dies for my rifle loading. If the OP goes the route of trying a M die - I would advise getting a Lee universal flaring die and going with the expanding/flaring plugs from NOE that can be used with the Lee die. Over time, as I added new cartridges, I added new M dies for them - and it adds up dollar wise. If a person was stating out loading rifle and or pistol, in the long run it would be cheaper to go with the Lee die and buy the NOE expanding/flaring plugs. You could assemble a pretty nice "set" of various size plugs without spending the amount it would cost to buy individual M dies for each caliber. While the M dies consist of a "long" or "short" body die, depending not he cartridge - I guessing that you could also buy individual M die stems for the calibers but it still seems like the Lee die with NoE plugs would be a cheaper way to go and do everything a person wanted?

[Bazoo]

Bedbugbilly, I've given thought to the noe M die plugs and lee die body vs the Lyman m dies. The advantage would be the various larger sizes in my view. I hate having to readjust a die ever time I change calibers. I'd rather pay 20 bucks and have a dedicated M die for each caliber I load, at least the most loaded. I haven't changed over yet but I'm wanting to go the M die path for my pistol calibers over the belling dies.

[MostlyLeverGuns]

I run NEW cases through a neck sizing die without the expand/decap rod (Redding, Redding Bushing, RCBS, Lyman...) then I chamfer inside and out. I then expand neck with Lyman or NOE 'M' type neck expander. Dragging an expander ball thru the neck, new or fired can lead to crooked cases. I full-length or neck-size without expanding case neck, THEN use the Lyman/NOE neck expander for all bullets, lead or jacketed. I have crumpled a few cases or damaged some bullets before I settled on this process.

[EDG]

You cannot seat any old bullet into any old case without looking and feeling what you are doing.
I have loaded many .38 Specials, .357 Magnums and .35 Rem over the years and have never had that problem.
Most of the loads for the .35 Rem were for the 180 grn Speer rifle bullet. I have not had any problem with it either,
but the large flat nose on many bullets will refuse to allow a crooked bullet to right it self. I can feel a bullet that is crooked and I spin the cases with a finger as they enter the seating die so the flat bullet nose enters the cone of the seating punch.
If this does not work an M die is used to expand the cases but so far I have only used the M die on cast bullets and for straight cases.

What you want to watch out for are some loading dies have a built in crimp shoulder. When you run a bullet into the seater the wide flat nose of the short 180 grn Speer bullet allows it to tilt over and catch on either the crimp shoulder of the seater body or on the edge of the seating punch. Such a tilted bullet will ruin you cases. Spinning the case as you run the bullet up helps too. When the bullet tip catches in something even an M die will not cure the problem.
I have used the 220 gr Speer also and it has the same bullet tip but it is longer and does not tip over a much or as far but it can have the same problem in some dies.
Pistol bullets will also ruin cases by tilting over and catching the interior of the die. You just need to use M type dies and spin the case if necessary. Sometimes you may have to change brands of seater dies.
I have used the 200 grn Rem core Lokt RN and spitzer bullets, 200 grn Sierra, and 200 grn Hornady RN and spitzer bullets in the .35 Rem.
All of these bullets are short and may have a tendency to tip over. The Hornady bullets have a huge base radius that helps prevent the problem.
This sort of problem also occurs with the flat edges of the 300 grn Hornady .458 rifle bullet in some dies. Just do a better job of expanding your cases and be sure the bullet is not tilting and catching the interior of the die. Spinning the case helps the nose of the bullet jump off of the edge so it can straighten up. More expansion of the case mouth so the bullet base starts out entirely inside the case helps keep the bullets straight.

[1hole]

I don't think your die or bullets did that; your photos show the end result of trying to push a solid plug (bullet) into a too small hole (case mouth) that's being firmly held too small by the die's crimp ring due to improper seater die body misadjustment. No mouth chamfer, two thou of oversize bullets nor lack of mouth flaring should be causing that much case mouth/neck deformation.

I wonder ... do you have your seating die set so far down that its crimping ring has firmly pinched off the case mouth before bullet entry even starts? Try backing your seater off a couple of turns and readjust the seater plug down, then seat one of your largest bullets and see what happens.

Lee's "Universal Expander" die is a good tool if you need it but the "expander" part of its name is a misnomer. It's only a universal mouth flaring tool, it's not at all a neck expander in the technical sense reloaders need. Lyman's very old "M" die (and it's RCBS/Redding copies) has long been the best expander/flaring plug design on the market for both jacketed and cast bullets. (I don't know if I could comfortably reload much of anything without my collection of "M"s.)

[lightload]

Problems like those above are one reason that some of us may use a die set made up of different brands. I always chamber and then bell case mouths, a practice that prevents problems. Ditto for M dies.

[Tripplebeards]

UPS already picked up my two boxes of bullets or I would’ve tried to go through and flair the necks. I’ll see what Speer says when they receive them in a couple days. RCBS is sending a out a replacement ball/primer pusher insert as well. I headed to the range today to try out the five ladder loads of H322 with the 180 grain speers I loaded up. All the groups were not impressive accept for one. 59.5 grains of H322. I seated my bullet .002” farther out than Hodgdon’s website. The book load max loading was 58 grains and said it was 48,000 CUP. SAMMI says 52,000 CUP is max for the Whelen so I did the math and loaded in .5 increments to 60 grains with zero signs of showing pressure. I figured Sixty grains should still be at or right under 51,000 CUP. I remember a couple of the bullets in my ladder test reloads seated harder than others. I also saw a shaving or two of copper from the bullet around my crimp on a couple. A shaving must have stayed in the chamber as it made an impression on the side of a fired cases.

59.5 grains of H322 is the winner. This is a three shot group at 100 yards. The barrel gets pretty hot after three rounds and if I ever had to shoot more then three times at a deer I’d pack it up and go home. I remember the 59.5 grain load was one of two loads that all three bullets felt like they were seated smoothly with even pressure. I also crimped them with my lee custom 35 whelen collet factory crimp die.

Not bad for a 7600 pump gun...


https://i.imgur.com/kohQxxe.jpg


When the bullets come back and I get my replacement expander ball from RCBS I’ll go through the motions and try and load one up without flaring the neck case first. If I feel any resistance I’ll be flaring them all from now on.

[megasupermagnum]

These are flat base bullets, correct? Yes, you need to flare the case. You always need to flare cases, the one single exception is a boat tail jacketed bullet can self center itself. Other than that one exeption, all other bullets jacketed, cast, or other, require the case to be belled. You can get away with way less with a jacketed bullet than cast, but the bullet base needs to be able to start into the mouth regardless.

[Tripplebeards]

I must have gotten luck all these years since I haven’t had any issues loading the same bullet in my 35 Rem cases. Also Ive loaded 1000’s of 60 grain flat base hornady vmax and .308 RP core loct bullets with zero seating issues.

[onelight]

I must have gotten luck all these years since I haven’t had any issues loading the same bullet in my 35 Rem cases. Also Ive loaded 1000’s of 60 grain flat base hornady vmax and .308 RP core loct bullets with zero seating issues.
I think I am lucky to , never had that happen loading for 356 and 358 winchester with many brands And styles of jacketed bullets loaded with 2 die RCBS and Lee dies.
But like EDG pointed out go slow and feel the process to get feed back from the tools.

[GarrettP1]

I love the 35 Whelen, and I shoot the AI version.

May I suggest: neck size only.
So much easier, and I never get crumpled cases.
IMHO Hornady makes the best neck sizing dies (I'm not a shill for them).

[Tripplebeards]

I use them in pump rifle so imo I need to bump the shoulders back for reliable feeding.

[megasupermagnum]

I must have gotten luck all these years since I haven’t had any issues loading the same bullet in my 35 Rem cases. Also Ive loaded 1000’s of 60 grain flat base hornady vmax and .308 RP core loct bullets with zero seating issues.

You've seated flat base bullets in non-flared brass? I've tried it a couple times myself, and I just don't see how it can be done. The bullet base on jacketed bullets is slightly rounded, but it still wont sit on the brass. You kind of half teeter the bullet on there, run it into the die, and half the time you get the result you posted. I've never heard of anyone seating without flaring (except some jacketed boat tails).

It seems a heck of a lot easier to just flare as intended.

[1hole]

UPS already picked up my two boxes of bullets or I would’ve tried to go through and flair the necks. I’ll see what Speer says when they receive them in a couple days. RCBS is sending a out a replacement ball/primer pusher insert as well. I headed to the range today to try out the five ladder loads of H322 with the 180 grain speers I loaded up. All the groups were not impressive accept for one. 59.5 grains of H322. I seated my bullet .002” farther out than Hodgdon’s website. The book load max loading was 58 grains and said it was 48,000 CUP. SAMMI says 52,000 CUP is max for the Whelen so I did the math and loaded in .5 increments to 60 grains with zero signs of showing pressure. I figured Sixty grains should still be at or right under 51,000 CUP. I remember a couple of the bullets in my ladder test reloads seated harder than others. I also saw a shaving or two of copper from the bullet around my crimp on a couple. A shaving must have stayed in the chamber as it made an impression on the side of a fired cases.

59.5 grains of H322 is the winner. This is a three shot group at 100 yards. The barrel gets pretty hot after three rounds and if I ever had to shoot more then three times at a deer I’d pack it up and go home. I remember the 59.5 grain load was one of two loads that all three bullets felt like they were seated smoothly with even pressure. I also crimped them with my lee custom 35 whelen collet factory crimp die.

Not bad for a 7600 pump gun...


https://i.imgur.com/kohQxxe.jpgWhen the bullets come back and I get my replacement expander ball from RCBS I’ll go through the motions and try and load one up without flaring the neck case first. If I feel any resistance I’ll be flaring them all from now on.

A different expander ball isn't likely change anything for you.

[Tripplebeards]

I called speer today to see if they had a chance to look at my bullets. Speer told me that some were larger than their max acceptable spec range so they are replacing the two boxes I sent in with new replacement bullets. The Speer customer service rep told me they still should have not been far enough out of spec to crush case necks and figured my RCBS expansion ball was out of spec and to blame. RCBS did sent a replacement primer knock out rod with expansion ball so I’ll have to measure both when I switch them out. Speer told me When seating the .358 hot cores in bottle neck cartridges I should not have to flare my case necks. I’ll give it a try with the new components and see what happens.

[Tripplebeards]

I wanted to follow up on this thread. I received replacement bullets from Speer and a replacement expander ball from RCBS. I also changed out my flat seater die to a conical seater die thinking it would help center my bullets into the case necks. I had a chance to try it out this morning and loaded up 25 rounds without an issues today. I can say it still requires a little bit more force than any other round have loaded for in the last 25 years...but they all seated just fine. It's just when the bullet first stretches the case neck is where the resistance is and then it slides smoothly the rest of the way down while seating it. I still used my Lee collete factory crimp die since I used it to dial in my load previously even though I can tell there is a good amount a neck pressure from the way my j words seated. A few seated with less pressure than others for some reason. All brass was new virgin RP and sized and trimmed the same.

[osteodoc08]

I didn’t read through the entire thread so this may have been mentioned but a few things come to mind.

1. Check the expander button and measure the I.D. Of the sized case. I like around 0.02” difference to maintain nice even neck tension.
2. Chamfer the neck.
3. Use a Lyman M die. I use these for my problem children Cast and keeps me from sizing them down by mistake

And by the way, been there, done that brother!

[gwpercle]

I’ve heard of the M dies but never seen or used one. How do they work?

If you load several different calibers and diameters a better deal is to buy A Lee Universal Neck Expanding Die , it actually just flares the mouth... But NOE makes little M-die inserts to be used with this die...cheaper than a Lyman M-Die and the NOE M-die insert comes in many diameters .
It's the neatest set up and works better than the Lyman die .
Also lots of times you simply want to flare a neck ...like when using J-word bullets ...the Lee Universal Die will flare all calibers ...it's good to have on hand .
From your photo's ...the crumpled cases need just a bit more flaring (belling) ...
Gary

[Tripplebeards]

I own the Lee univeral expander die. I use it for cast. Never thought I would need to expand the necks for j words. Both RCBS and Speer told me I should not have to flair case necks with jacketed bullets. Both told me my issue was either an an out of spec, oversized bullet or undersized expander ball. Im happy to say the issue is now fixed whether it was the bullets, expander, or seater I dont know. Not going to wreck another expensive factory RP 35 whelen case to find out which one it was. I did measure the the replacement expander ball and it was the same size at the original. I'm guessing the bullets were to large in diameter as Speer factory reps told me they were larger than max spec. I'm sure my flat pusher insert didn't help as I'm guessing it wasnt aiding in perfectly linking up the bullet with my case either.

[Three44s]

I read this thread back at its inception and decided to stay out because you had so many responders hitting the nail on the head I figured I would keep out and observe.

Just about every thing that might be said has been posted ..... almost.

While I fully concur with the “M” die recommendation, there are two things I want to add to this mix:

Your brass is likely quite soft (it’s new) and that adds to the problem. As you fire, size and fire again, your case mouths will become more brittle. If you anneal your neck and shoulder region you will go back there again.

Lots of folks avoid case trimming but I do not.

Here is what I would do: I would get all my brass uniform in length unless a case or two were way short. Then I would chamfer the inside of my cases and debur the outsides. Yes they are new but just do anyway. I like the new chamfer tools that are VLDs. You may even use a VLD and a standard angle one in succession.

Next I would use a Lyman M die and carefully expand the case mouths to make your cases belled enough but not excessively. As an alternative the NOE plug for your Lee Universal tool may be fine but I do not have experience with them. Any way you go however I prefer the M die result much better than the Lee flare. The Lyman does a two step. That is much better. If the NOE plug fully gives you that true two step then bully for NOE!

The reason I am preaching to uniform your case length is to give your cases mouths the same bell from number 1 to the last case you bell. The extra care with a inside case mouth chamfer tool saves extra belling just like having your cases uniform in length also reduces having to bell more.

Remember, it is like bending a wire back and forth. Do it enough times and then you have two pieces. The same with your brass, over work it and it hits the trash can sooner.

You can send bullets to Speer and they blame the die manufacturer. Send the expander to RCBS and cold water gets thrown at the bullet maker, but you are stuck in the middle.

The next thing we want to avoid is having a seating die BODY set too low. Many respondents warned you about that. I always, ALWAYS set my TRIMMED case in with no bullet and raise the ram and bring the seater die down to just kiss the crimp ring of the seater die to the case mouth and then screw it back up a bit. You must maintain clearance unless you want to crimp while seating.

Now I roll both ways on this subject as some I seat and crimp in one operation. Others I do separately. But if you do both together you are running a risk of inducing a neck collapse. So often even if I am crimping with the same die I will still separate the operations.

While I do not trim brass upon each loading, I am very reluctant to seat and crimp cases that have been fired enough to vary in length.

I am a big proponent of rotating a case as I begin seating a bullet. You want to avoid forcing a bullet that is leaning into your case mouths. I call the process “mini pushes”.

A press without compound leverage is actually an asset here for belling and seating because you have better contrast in pressure differences than with a compound press.

As the bullet leans you relax, rotate and re-push. You move the press ram ever so slightly higher then relax and rotate the case 120 or so degrees and push again.

I particularly do the rotate case business with my varmint ammo but in the case of collapsing necks, I would target that ammo with it as well. It can help with accuracy and reduce case los. What’s not to like?

The final item is a tilted bullet catching it’s crimp cannelure on the edge of the case mouth. All the steps I have outlined to this point either precludes that or reduces the chance of it including the mini push, rotate process.

Lastly, since you had to bell your case mouths, even if I do not care to actually crimp my ammo, I make certain that the bell is flattened.

So that is my .02 worth

Enjoy!

Three44s

[Tripplebeards]

Three 44’s you and I load the same. I trimmed, chamfered, and deburred all of these brand new cases. I do this with every case, every time I reload. Long lengthy process but I want to keep it consistent. I also rotate my cases as soon as the bullet starts to seat for nice even seating. If it wasn’t the bullet it was my fault with the seater insert I stoned flat . I did this to flatten out the finning on my cast HP boolits. Im sure It caused the jacketed bullets to unevenly seat. It works great for big flat metplates like the lee 300 grainers in 44 and 45 cal but believe it was probably part or all of the issue with my 35’s. I did this to avoid cutting a ring around my cast 35 Rem boolits when seating them. It worked but also widened and flattened my HP cavity so I stopped using it. I forgot that I installed it in my 35 Whelen seater die when loading cast in it previously. By installing the conical insert it keeps the HP in its narrower taper so it feeds better in my pump and lever actions as well.


Here’s a pic of it after I stoned and oxpho blued it. I’m sure with an uneven soft lead tip on my hot cores were causing an uneven seating. Like I said above they now seat but I still have a good amount of force to do so right when the case lip expands over the bullet base then it’s smooth sailing. I’m sure it’s the new brass and the bullets will slide in easier next loading. I’ll keep my stoned flat seaters for the 44 and 45’s. I’m sure most or all of this issue was caused by me and my flat seater die. Thanks for the help.


https://i.imgur.com/aY9285Q.jpg

[Three44s]

Tripplebeards,

Oh, I think the bullets indeed triggered the problem alright. I feel a sort of bulge at the bases of j words with supposedly square bases from time to time.

Glad you brought up the matter about your custom nose punch though because that could reduce the effectiveness of mini push bullet seating.

Many years ago a then retired volunteer fire fighter told me his theory on accidents:

He said that an accident consisted of a chain of events. Along the way, each link was another step towards the incident. It did not occur (at least rarely) because of just one but rather it took some set of them being unbroken the accident to happen.

In the instance of your damaged cases, I think some of that theory applies. You had some factory bullets a wee bit out of spec, you were working with new soft case mouths and your seater plug may be causing a rigid alignment of the bullet to the case mouth and you were not belling the case mouths because you had not experienced this situation before.

Something else I thought of that could help is to use a wrench socket filled with steel wool spun from a drill applied to your case mouths. This polishes the ragged burrs left from chamfering your case mouths.

The other thought is to very, very lightly lube your bullet bases. Something that dries or a sparing hint of a wax lube ..... the tub from Lyman labeled Ideal?

Three44s

[1hole]

Needs more inside chamfer or bell the mouth

Those appear to be new cases. Chamfering alone will probably be enough to let the bullets get started without hanging up on the mouth. A little belling/flaring will assure it.