45 ACP Bullet Setback - Zero 185 gr JHP

[Ruger 15151]

I recently had a new match KKM barrel fitted to my SA 1911 by a reputable bullseye smith. I broke the barrel and slide in with 200 gr LSWC and a light load of 3.4 gr of BE. No issues for 250 rounds.

Last night, before I started loading some Zero 185 gr JHPs, I made some dummy rounds just to make sure they would cycle and to check the setback. The dummy rounds were loaded to COL 1.205 with a .468 crimp. I'm also using a 12# recoil spring.

When I release the slide stop to load the rounds and then eject them, I was getting bullet setback that ranged from .004-.008.

I have read that there are different magazine follower that might help. Some guys say they cut 1-2 loops off the springs.

Any one else have these issue or have some suggestions for a cure?

 

[ATLDave]

I am having a hard time figuring how a different magazine follower would change setback. And, if it could, why a lighter spring would help setback... the only plausible role of the mag in setback that I can think of is a magazine that doesn't get the nose of the round fully lifted into the ramp before the slide works it forward.

I'd tend to look at the usual setback suspects: bullet diameter, brass brand, sizing die dimensions, expander size and depth, and crimp die setting.

 

[Blue68f100]

That's either a sizing or expanding problem, maybe crimp, has nothing to do with the mags. Measure the bullet dia and your brass ID should have 0.003". if the bullets are < .452" as they should be for lead the bullets may be too small. Also depending on brass some have thinner walls. So something else to check. You can always turn down the expander if it's too large.

Back off your crimp too. .468 is too much, should run around .470". Over crimping will loosen the bullet up.

 

[Walkalong]

Sound advise above, but one thing to consider is if you don't do that repeatedly it isn't an issue.

Size one of the thinnest (Thinking RP here) cases and seat a bullet without using the expander. If it has enough neck tension to stop the setback the expander is too large. Get a Lyman M-Die expander or the new RCBS and Redding expanders that have basically copied them. Good stuff regardless. Check again. If you still don't have enough neck tension your sizer is toolarge for the thinner brass, get a new sizer or scrap the thin brass.

My CZ 97 loves that bullet.

 

[ATLDave]

Size one of the thinnest (Thinking RP here) cases and seat a bullet without using the expander.

I almost asked if this happened to be with R-P brass. I can get .45 R-P brass to hang onto lead bullets but they will not grip a jacketed or plated bullet for me. Setback city!

 

[Ruger 15151]

I am having a hard time figuring how a different magazine follower would change setback. And, if it could, why a lighter spring would help setback... the only plausible role of the mag in setback that I can think of is a magazine that doesn't get the nose of the round fully lifted into the ramp before the slide works it forward.

Checkpoint makes separate magazines specifically for ball ammo and wad cutters/hole points. From what I have read, the feed lips and followers are shaped differently to better guide wad cutters/JHPs into the chamber. I have read on the bullseye forums that guys will lighten the springs by cutting off a coil or 2. They claim too heavy of a spring hold the cartridge too hard against the feed lips and follower causing it to nose dive slightly as it enters the chamber. I know Wolff makes different weight magazine springs

Again, this issue is new to me so I am still looking for solutions.

 

[ATLDave]

Interesting. If you're interested in understanding/exploring 1911 magazine geometry, you may enjoy this series of articles: http://how-i-did-it.org/magazines/

I found it helpful when I was trying to troubleshoot a picky 1911, although it's not a troubleshooting guide per se.

I will say this: one of the things I ended up doing as a result of my troubleshoot was to no longer use R-P brass, which was so prone to setbacks that the geometry of the round would change during feeding and sometimes jam up.

 

[Ruger 15151]

That's either a sizing or expanding problem, maybe crimp, has nothing to do with the mags. Measure the bullet dia and your brass ID should have 0.003". if the bullets are < .452" as they should be for lead the bullets may be too small. Also depending on brass some have thinner walls. So something else to check. You can always turn down the expander if it's too large.

Back off your crimp too. .468 is too much, should run around .470". Over crimping will loosen the bullet up.

I load on a Redding T-7 and I am using a Redding sizing, expander, and profile crimp dies. I also have the Lyman M-Die and the dimensions within .001 of the Redding die.

I generally use a .471 crimp on .022 thick cases with standard loads. However, this pistol is set up for soft bullseye loads. The bullseye guys recommend .468 - .469 for lighter loads and fast powder because they want the case to hold onto the bullet a little longer..

 

[Ruger 15151]

I will say this: one of the things I ended up doing as a result of my troubleshoot was to no longer use R-P brass, which was so prone to setbacks that the geometry of the round would change during feeding and sometimes jam up.

Thanks Dave. I will take a look.

BTW - I was using once fired Starline brass for these rounds.

 

[ATLDave]

Welp, there goes that possible root cause!!

 

[CKweigand]

I usually adjust my dies to accommodate R-P Brass, I have so much of it. To throw to the wayside is a huge waste IMO...Yes it is thin but it is consistent from what I’ve experienced. Walkalong nailed it on the head above, sounds like an expanding issue and are overworking the brass maybe.

Something to consider before cycling them through the gun. Try the bathroom scale test. It catches setback quickly and easy to correct from there.

 

[Ruger 15151]

Bathroom scale method?

 

[murf]

load up a round (don't need primer or powder for this just size, bell, crimp and seat), measure col, push bullet end down on the bathroom scale (20 lbs, 30 lbs, etc.) and remeasure col. measurements should be the same for all weights.


what is the outside diameter of a sized case (up around the mouth)? and what is the brand of case used here?

murf

 

[CKweigand]

Some people prefer to cycle the rounds through their firearm and then check any deviations in COL.

Some people prefer to push their rounds against their bench and then check the measurements.

Another way is to use an old bathroom scale. Push the round down to a constant 40# for say 3 seconds and then check...it’s just a consistent way to use the same amount of force for multiple rounds. That way your not pushing one and wondering if you pushed just as hard on the next.

 

[Walkalong]

They claim too heavy of a spring hold the cartridge too hard against the feed lips and follower causing it to nose dive slightly as it enters the chamber.

This does happen, especially with the first round in an 8 round 1911 mag.

But that isn't your main issue.

That said, get a "wadcutter" style mag that releases the round earlier. Don't jam it full. And check a round(s) without the expander.

 

[Ruger 15151]

This does happen, especially with the first round in an 8 round 1911 mag.

But that isn't your main issue.

That said, get a "wadcutter" style mag that releases the round earlier. Don't jam it full. And check a round(s) without the expander.

Good advice! Thanks everyone! I’ll report back once I find which suggestion is the cure!

 

[Walkalong]

As an aside, I looked it up and I am loading the Zero 185 Gr JHP @ 1.220 to 1.225 OAL.

Maybe load it a hair longer? Something to try, but it should help a tiny bit with a round that tries to nose dive. Maybe?

 

[Rule3]

As an aside, I looked it up and I am loading the Zero 185 Gr JHP @ 1.220 to 1.225 OAL.

Maybe load it a hair longer? Something to try, but it should help a tiny bit with a round that tries to nose dive. Maybe?

This is what I do not understand about "setback" yes I know what it is and if too much can cause pressure issues but if the OP has a variance of .004-.008 and you load to .005 variance, I do not see an "issue"?? Seems insignificant to me?

There again I do not see how a Magazine and or spring has anything to due with it either, To me it's brass, sizing, flaring, crimp or all of them.

 

[Walkalong]

I do not see an "issue"?? Seems insignificant to me?

Sound advise above, but one thing to consider is if you don't do that repeatedly it isn't an issue.

 

[Walkalong]

There again I do not see how a Magazine and or spring has anything to due with it either,

With a lot of spring pressure on the rounds pushing them up the case drags along the feed lips, and when the front part clears the feed lips the drag can cause the whole round to tilt down, into the feed ramp, because the breech is pushing against the top of the case head while the feed lips are dragging on the bottom of the case trying to hold the round back. It's worse in 1911 mags that hold 8 rounds and have a stiff spring. This is why they started going to a bit longer tubes in the 8 round 1911 mags.

 

[Ruger 15151]

There again I do not see how a Magazine and or spring has anything to due with it either, To me it's brass, sizing, flaring, crimp or all of them.

Depends on the purpose. If you are reloading to hit a steel target at 10-15 yards than you are correct. However, if you are looking to hit a 1.7” x-ring at 25-50 yards, there are a few more variables to consider.

 

[Rule3]

Depends on the purpose. If you are reloading to hit a steel target at 10-15 yards than you are correct. However, if you are looking to hit a 1.7” x-ring at 25-50 yards, there are a few more variables to consider.[/QUOTE

I guess, If you feel that .004" difference in seating depth has that much effect on accuracy when "there are a few more variables to consider",or in reality many more variables. Then by all means erase that variable

Seems most agreed with ammo related but if you feel a new mag, follower or spring will correct then go for.

Sure would like to see the actual difference showing that is what it is..

All that aside, I still do not think cutting mag springs would be the first method of solving bullet set back with all the other more probable things to try.

There are many many threads out there in internet land and it is a definite, maybe, sort of, sometimes, almost always.could be the mag.

Very undecided, but seems most claim its ammo related.

Good luck in your solution's,

 

[Jim Watson]

Lee or EGW "U" die will size the brass smaller and give the "Coke bottle" shape to prevent setback.

 

[AJB2]

Wolff makes different strength mag springs . For mags I use the Metalform either rounded follower for wad loads or flat w/ the dimple for ball . If I load the Nosler or Zero JHP I use coal of 1.210 & .469 crimp . KKM barrels like the Nowlin use a special reamer . Check the installed depth of your chamber . Pull barrel out & do a " plunk " test " with your reloads . If case head is flush with or below end of barrel hood you should be good . If not you can either reduce your OAL with that bullet or get your chamber / throat reamed if it's too short . Can you chamber a factory 230 FMJ round ?

 

[Ruger 15151]

Wolff makes different strength mag springs . For mags I use the Metalform either rounded follower for wad loads or flat w/ the dimple for ball . If I load the Nosler or Zero JHP I use coal of 1.210 & .469 crimp .

Thanks everyone for the suggestions. But I think Walkalong and AJB2 have zeroed in on the issue I am having. I probably should have posted in a different forum on THR because the issue I am having isn't really related to reloading. All the dummy rounds pass the pluck test and the chamber fine. Factory 230gr Ball ammo chambers with no issues.The bullet setback is occurring because the bullet is not entering high enough on the barrel feed ramp to chamber smoothly.

I use Metalform 7 round mags with the round follower. This is a newly fitted barrel and I have only shoot 250 rounds with Magnus hard-cast 200gr LSWC. They all cycled perfectly so I am confident the chamber is fine. However, my issue is with the shorter 185gr JHPs. I used black marker to die the feed ramp, transition, and barrel ramp to see where the nose was hitting. At 1.225 COL, the initial mark was on the feed ramp and if I released the slide very slowly, the bullet tip on the feed ramp would actually keep the slide from closing . At .1200 the initial mark was low on the barrel ramp but still didn't feed into the chamber smoothly.

I decided to use the stock SA 7 rd mag as a tester. I cut one coil to reduce the spring tension and bent the follower up about .020. This released the bullet a little higher. Now all 7 dummy rounds will chamber without nicking the tip of the bullet an I am not seeing any setback.

Although I don't think this is the ultimate solution, it seem to work on the bench. Now I will have to shoot it to see how it cycles.

Thanks again to everyone who provided constructive suggestions. I love tapping into the vast brain trust here on THR.