"Stepped " Boolit in 9MM

[wv109323]

I have( 2) 9mm handguns in which the rifling extends to the end of the chamber. One is a CZ 75 and the other is a CANIK. In other words there is no leade in the barrels and oversized cast bullets will hit the rifling before the slide is in full battery. To avoid this the boolit has to be seated so deep in the case, I fear high pressures from reduced case capacity.
One solution is to have the throat reamed to allow longer OAL. I have had this done on the CZ but I still can not find reasonable accuracy with the pistol. It seems the leade is .356 and the bore is .3563. My thoughts are the throated area is down sizing my bullets the same way the cylinder throats down size a revolver boolit before the boolit enters the revolver barrel.
Any way my groups really open up when I load above 850 FPS. I have tried probably 25 bullet sizes and configurations with 10 different powders. Even jacketed bullets tend to have poor accuracy above 850 FPS.
So my question is: Has anyone had success with a stepped bullet where the ogive is stepped down from the main boolit diameter? If so what weight and mold?
In my reading the foreign specs for a 9mm chamber are different than SAAMI.

[Hick]

I have good results with a Lee truncated cone boolit. I set so the conical portion starts right at the case mouth. Its the tumble lube version but I use PC on it

[Kenstone]

Missouri Bullet Company makes/sells this stepped bullet, powder coated:
https://missouribullet.com/details.p...ry=8&keywords=
Same bullet wax lubed:
https://missouribullet.com/details.p...ry=8&keywords=
Take a look,
OK, some more:
I buy 38 bullets and push them thru a Lee sizing die (I have 3 different sizes) for 9mm and often leave them big (0.357 dia.) for better accuracy in 9mm guns with oversize barrels.
These have steps but are "38s" and may need re-sizing:
https://www.snscasting.com/38-357-12...coated-1000ct/
0.356 dia. stepped/coated:
https://bayoubullets.net/9mm-95-gr-rn/

[475AR]

I designed an Accurate Molds bore riding TC 9mm bullet that shoots very well in my guns so far. It cast about 155gr and feeds thru everything I have shot it thru. I wanted a heavier cast bullet for suppressed use and wanted to make sure that fully seated did not go deeper then .300" into the case (because going deeper the base of the bullet starts to swage down due to the taper in the case walls.) These seat to a COL of 1.14".


I am still in load development and hope to settle on a specific load then tune it for accuracy and will post pics when I can.

[Bigslug]

Something shaped like the Accurate 35-125B or 35-130A might solve your problem, but if you've already reamed the throat, I don't see how.

I'm also puzzled as to how your leade can be smaller than your GROOVE diameter, unless you're discussing the beginning of the lands. The BORE of every 9mm I've pin gauged so far has been .346"-.347" (including polygonal and "Marksman" Glocks and a Hungarian BHP clone). A pound casting of your chamber might be in order.

My advice would be to FATTEN up your nose to work within the space you have. I'm running the NOE TL357-135-RF "Ranch Dog" which is very nearly the same bullet as Accurate's 35-135D. I call your attention to the blueprint on the Accurate:



Note the taper from the end of the .357" diameter shank to the .345" diameter at .357" forward of the base. If your brass is taper-crimped to the regulation .380" O.D. at the mouth, and you're seated to where the beginning of that taper starts at the case mouth, it would be a very tight chamber and throat indeed to stick on that profile.

For accuracy. . .you might measure your case wall thickness, then pin-gauge the interior of a fired case and the front end of your chamber to see if you have enough room to get correct cartridge dimensions while seating a .358" diameter bullet. My bore sluggings on the same guns as above have given me groove diameters of .355"-.356" and .357" bullets seem to work, but fatter may help you out.

ALSO: is it possible your brass is sizing down your bullets on seating? The obvious indicator of that would be lead fouling, but if added speed is causing your accuracy woes, I think this may be the problem. Might be worth pulling and measuring one of your bullets to find out. Your factory dies are probably spec'd for a .355" diameter jacketed pill, which is not what we're playing with. I ended up using a Lee .38 S&W sizing die to get a little more expansion to prevent this.

Hope that gets you up and running.

[Kenstone]

Something shaped like the Accurate 35-125B or 35-130A might solve your problem, but if you've already reamed the throat, I don't see how.

I'm also puzzled as to how your leade can be smaller than your GROOVE diameter, unless you're discussing the beginning of the lands. The BORE of every 9mm I've pin gauged so far has been .346"-.347" (including polygonal and "Marksman" Glocks and a Hungarian BHP clone). A pound casting of your chamber might be in order.

My advice would be to FATTEN up your nose to work within the space you have. I'm running the NOE TL357-135-RF "Ranch Dog" which is very nearly the same bullet as Accurate's 35-135D. I call your attention to the blueprint on the Accurate:



Note the taper from the end of the .357" diameter shank to the .345" diameter at .357" forward of the base. If your brass is taper-crimped to the regulation .380" O.D. at the mouth, and you're seated to where the beginning of that taper starts at the case mouth, it would be a very tight chamber and throat indeed to stick on that profile.

For accuracy. . .you might measure your case wall thickness, then pin-gauge the interior of a fired case and the front end of your chamber to see if you have enough room to get correct cartridge dimensions while seating a .358" diameter bullet. My bore sluggings on the same guns as above have given me groove diameters of .355"-.356" and .357" bullets seem to work, but fatter may help you out.

ALSO: is it possible your brass is sizing down your bullets on seating? The obvious indicator of that would be lead fouling, but if added speed is causing your accuracy woes, I think this may be the problem. Might be worth pulling and measuring one of your bullets to find out. Your factory dies are probably spec'd for a .355" diameter jacketed pill, which is not what we're playing with. I ended up using a Lee .38 S&W sizing die to get a little more expansion to prevent this.

Hope that gets you up and running.

I have replaced the 9mm Lee expanding/flaring PM plug with a Lee 38 S&W Plug and it's a direct replacement, no need to buy a complete die.
That powder thru expander plug is longer and expands deeper in the case, something that is good if shooting heavy/long bullets.
https://www.titanreloading.com/produ...h=Lee%20SE1699
https://leeprecision.com/pm-expan-plg-38-s-w.html
Cheap enough to buy several and stone them to whatever size is needed.

9mm is the shorter expander, 38S&W is the longer:

.

[gwpercle]

The NOE boolit mould design 358 - 124 - TC is designed with a step just as you describe ...
I have used it in 4 different 9 X 19 handguns 2 full size , one compact size and one sub-compact , all were made to function 100% with slight OAL adjustments for the compact and sub-compact ...those had no leade / throat ...chamber ends and rifling begins . The stepped NOE design solved the problem , none of the 4 pistols barrels were throated ... it's a proper design for barrels with little or no throats .
I also ordered the mould cut for a gas check ... that solved / eased boolit seating and shooting 1000 fps loads with a alloy of 50-50 COWW and soft lead (I don't powder coat in 9mm that just makes things worse) . For use in 9mm size to .357 in all 4 pistols . Size to .358 and I use in 38 Special +P , 357 Magnum loads ...sweet and versatile boolit !
Do Not Fear the Gas Check in this application ... it realy helps solve several problems and opens the use of this boolit !
Gary

[Forrest r]

Interesting but confusing

How would a "stepped" bullet do anything for accuracy in a bbl that has a .356" leade and a larger bore diameter?

A .360" wc bullet loaded and hand fed into the chamber and fired would be sized down to .356" in the leade. So would any of the bullets that are recommended. Yes they can be loaded longer but what happens to accuracy when the undersized bullets leave the chamber and go down the larger in diameter bbl?

[DougGuy]

I have( 2) 9mm handguns in which the rifling extends to the end of the chamber. One is a CZ 75 and the other is a CANIK. In other words there is no leade in the barrels and oversized cast bullets will hit the rifling before the slide is in full battery. To avoid this the boolit has to be seated so deep in the case, I fear high pressures from reduced case capacity.
One solution is to have the throat reamed to allow longer OAL. I have had this done on the CZ but I still can not find reasonable accuracy with the pistol. It seems the leade is .356 and the bore is .3563. My thoughts are the throated area is down sizing my bullets the same way the cylinder throats down size a revolver boolit before the boolit enters the revolver barrel.
Any way my groups really open up when I load above 850 FPS. I have tried probably 25 bullet sizes and configurations with 10 different powders. Even jacketed bullets tend to have poor accuracy above 850 FPS.
So my question is: Has anyone had success with a stepped bullet where the ogive is stepped down from the main boolit diameter? If so what weight and mold?
In my reading the foreign specs for a 9mm chamber are different than SAAMI.

I throat them so that they will take a .358" pin well into the throat. You can then seat out as long as the magazine will permit and have reliable feeding and decent groups.

25 boolits and 10 powders later, I think I would have called it off and did something different before now. Just have the barrel throated and move on with perfecting loads for this gun. Life is much too short to put up with mediocre results that fail to reward our efforts.

[joebaja]

I have really good results in my Canik with a couple of MP SWC designs. The HG275 clone is seated really deep, but gives excellent accuracy. The RN SWC (https://www.mp-molds.com/product/359...6-cavity-mold/) loads out a longer and runs well in just about everything I have tried it in. Both drop on the heavy-for-caliber side, so they are making USPSA power factor at lower velocities than you would have to push a 124. Not sure if that is a concern for you, but I have found in about every load that I have developed, the Canik seems to prefer heavy and slow over light and fast.

[Alstep]

DougGuy did my CZ barrel a while back. Cleared up all the problems you describe.

[gpidaho]

DougGuy did my CZ barrel a while back. Cleared up all the problems you describe.

Same with my Ruger 45 ACP barrel. Just have Doug throat it and don't fight a barrel that was meant for jacketed bullets. Gp

[Good Cheer]

I designed an Accurate Molds bore riding TC 9mm bullet that shoots very well in my guns so far. It cast about 155gr and feeds thru everything I have shot it thru. I wanted a heavier cast bullet for suppressed use and wanted to make sure that fully seated did not go deeper then .300" into the case (because going deeper the base of the bullet starts to swage down due to the taper in the case walls.) These seat to a COL of 1.14".


I am still in load development and hope to settle on a specific load then tune it for accuracy and will post pics when I can.

Nice looking boolit.

[Good Cheer]

475AR,
You have me thinking about something.
Long ago I adopted the practice with 45ACP target loads of using a boolit design that allowed seating out to engrave into the rifling when it went into battery. Nothing new there of course, just the same way a Feinwerkbau accepts a .22RF. But what you've spoinged into my thinking is adding a bore rider portion ahead of the groove diameter portion. And then oh but what should the nose look like? Why an adjustable length SWC nose of course!
Something new to think about while howling winds rearrange the drifts. Thanks.

[gwpercle]

475AR,
You have me thinking about something.
Long ago I adopted the practice with 45ACP target loads of using a boolit design that allowed seating out to engrave into the rifling when it went into battery. Nothing new there of course, just the same way a Feinwerkbau accepts a .22RF. But what you've spoinged into my thinking is adding a bore rider portion ahead of the groove diameter portion. And then oh but what should the nose look like? Why an adjustable length SWC nose of course!
Something new to think about while howling winds rearrange the drifts. Thanks.

Think about the NOE 358-124-TC , truncated cone design .
Al Nelson thought about this boolit when he designed it . It looks a lot like the Lee 355-120-TC design but with a couple tweaks that make it much better . The bore riding section you speak of is there and sized so it makes a difference in loading , shooting and accuracy .
check it out www.noebulletmoulds.com somewhere on the site are dimensioned drawings . I'm not computer savvy enough to get one from there to here .
Gary

[rockshooter]

NOE has several designs with the stepped nose. They are especially useful with powder coated bullets since one of the main complaints with PC is it makes the nose too fat and interferes with chambering. Two that I am quite happy with are 358-131-RF-R5 and HTC 356-135-RF-AH2. He has others with the same general stepped design. What I like is that he gives drawings of all his bullets.
Loren

[gwpercle]

NOE has several designs with the stepped nose. They are especially useful with powder coated bullets since one of the main complaints with PC is it makes the nose too fat and interferes with chambering. Two that I am quite happy with are 358-131-RF-R5 and HTC 356-135-RF-AH2. He has others with the same general stepped design. What I like is that he gives drawings of all his bullets.
Loren

LIKE LIKE LIKE !!!
Gary