Case bulging after reload

Crazy Horse said:

9mm FP ... I get a case that had a bulge along the center.

Has anyone experienced this effect? If so, where in the reloading process does it occur?

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The bulge you are seeing occurs during bullet seating.

When you resize a spent brass, the carbide sizer ring will reduce outer diameter of expanded case and make it longer. The reduction of case is needed to produce neck tension when the bullet is seated.

When bullets are seated, they will slightly bulge the case especially around the base of bullet due to thicker case wall. FP bullets have longer base length compared to RN bullets and makes the bulging more prominent.

It is normal as long as finished rounds will pass the barrel chamber. If you are using thicker case wall brass, case bulge may rub the tighter chamber of aftermarket/match barrels - https://www.thehighroad.org/index.p...nd-bullet-setback.830072/page-3#post-10713822

Here's a comparison picture of different bullets showing slight bulge



Here's a close up around bullet base showing good neck tension that is even around the case neck which indicates there was no tilting of bullet during seating.

Wasp waisted 9mm bullets are very common. If they plunk just keep going.

Agree with Live Life. The other thought is if the brass has an internal step that keeps the original bullet from setting back. Those brass I just save for now as the data is for regular brass that has normal case volume under the bullet. I have so many 9MM brass I probably will scrap them eventually though.

Crazy Horse said:

Thanks all. Out of 50, I only had one turn out like this on this go(wouldn't cycle) around . Wasn't sure on the cause.
The 147 gain FP bullets from RMR (heavy match winners) felt good. I wanted to make sure they functioned better than the previous match winners they had on their site (these are labeled as "heavy match winners"). Those match winners on there other hand, all sorts of problems with that bullet.

CH

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I shoot a pile of their 115 mw and prefer them to their rn option. The mpr is also good imo.

Crazy Horse said:

Thanks all. Out of 50, I only had one turn out like this on this go(wouldn't cycle) around . Wasn't sure on the cause.
The 147 gain FP bullets from RMR (heavy match winners) felt good. I wanted to make sure they functioned better than the previous match winners they had on their site (these are labeled as "heavy match winners"). Those match winners on there other hand, all sorts of problems with that bullet.

CH

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Can you explain what problems you had with the other MW bullets? Thanks.

I see factory white box 9mm that shows that. I get that every now and then loading and it has never been an issue ...ever. I admit, it tripped me out a little when I first started loading. lol

BOISE BADWOLF said:

I see factory white box 9mm that shows that. I get that every now and then loading and it has never been an issue ...ever. I admit, it tripped me out a little when I first started loading. lol

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I have a few samples of premium factory ammo that shows the “ bullet bulge”, too. Sometimes the case is a tad undersized but within spec.. and the bullet a bit oversized and within spec…and they meet creating a visible bulge.

These are SXT loads from Winchester in 9mm 127 gr +P+ and .380 persuasion (I tried to get the light just right to show the bulges):



As the guys said; if it plunks easily it’ll shoot in your gun.

Now, when you overcrimp a load that you’re putting together on your press you get a trophy like this one:



This bulged on one of the cannelures when crimping the coated .38 caliber SWC a bit too much. I think the case now has a weak area and is pretty much ruined, so I keep it on my shelf over the presses as a reminder that gorilla strength is not needed when loading.

(In the background is a factory load that caught the lip when being loaded, I pulled the bullet because it wouldn’t chamber in my .45’s.)

Stay safe.

From what I see in the pic is a normal bullet bulge. 9mm cases are tapered and some with thicker walls and deeper bullet seating will show a bulge at the bullet base. Look up the "Plunk Test". If I had any that would not plunk I would find out why (I have 4, 9mm pistols, use mixed brass, and 50% of the bullets I use are cast, some sized to .358".). Perhaps some brass with thicker walls, plus a bit fatter bullet, seated a bit deeper will bulge enough to have chambering problems with a "tight chamber" pistol.

Make sure your "Jamming" is from the bulge and not from excess OAL with the bullet hitting the rifling before shortening the OAL...

LiveLife said:

The bulge you are seeing occurs during bullet seating.

When you resize a spent brass, the carbide sizer ring will reduce outer diameter of expanded case and make it longer. The reduction of case is needed to produce neck tension when the bullet is seated.

When bullets are seated, they will slightly bulge the case especially around the base of bullet due to thicker case wall. FP bullets have longer base length compared to RN bullets and makes the bulging more prominent.

It is normal as long as finished rounds will pass the barrel chamber. If you are using thicker case wall brass, case bulge may rub the tighter chamber of aftermarket/match barrels - https://www.thehighroad.org/index.p...nd-bullet-setback.830072/page-3#post-10713822

Here's a comparison picture of different bullets showing slight bulge

Here's a close up around bullet base showing good neck tension that is even around the case neck which indicates there was no tilting of bullet during seating.

Click to expand...

And during the "crimping" process the top of the case can be reduced in size and result in the example in the OP.

JJFitch said:

And during the "crimping" process the top of the case can be reduced in size and result in the example in the OP.

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I disagree. I see taper crimp with sharp 90 degree case mouth against the bullet.

The bulge shown in OP's picture is near bottom of the bullet base and from bullet base pushing out on thicker wall portion of case as FP bullet has longer bullet base than RN bullet. The bulge was caused during the bullet seating process.

Crazy Horse said:

Out of 50, I only had one turn out like this on this go(wouldn't cycle) around. Wasn't sure on the cause.
The 147 gain FP bullets from RMR (heavy match winners) felt good. I wanted to make sure they functioned better than the previous match winners they had on their site (these are labeled as "heavy match winners"). Those match winners on there other hand, all sorts of problems with that bullet.

Click to expand...

You are NOT giving us all the information we need in a single post !

There is a specific issue with 147gr in 9mm Luger cases, which you must be aware of and watch for.



147's are physically longer, and therefore typically seat deeper into the case. However, the web of the case wall starts to thicken at a certain point. Not all brands of brass have this "case wall thickening" occur at the same place. If the base of the bullet runs into the start of the thicker wall, then the bullet will succeed in pushing the case outward.

- In those situations you will get a case bulge in the middle of the case wall.
- Due to the tapered chamber on the 9mm, this bulge may jam the cartridge part-way into the chamber. You will not be able to open the slide or close the slide.
- And if using "mixed brass", then you may only get this situation on 1 out of 200 reloaded cartridges.

As bullets go, the RMR 147gr Match Winners are more forgiving than some, but you still need to do your homework.

OK, if you are re-loading mixed brass, random bulges may be from stepped or thick webbed brass.
I have found steps in many brands of brass, even Speer as pictured here:

Blazer Brass (stepped)


Seating lighter bullets not a problem but seating heavier bullets deeper is a problem in brass like this.

So just another benefit of pin/wet tumbling over dry tumbling, seeing the inside of a case, not just a black hole .
Culling the cases with a step...

Edit: um, if you are NOT reloading mixed brass, then nevermind

I would suggest extra caution if one tries reloading stepped brass. The greatly reduced case capacity will result in excessivly high pressure if loaded to same specs an "norman" brass. Most/many reloaers toss stepped brass...