Acceptable bullet diameter tolerence

[horseman1]

Hi,

So when you all order/buy bullets (assuming that you don't cast your own and they are all perfect) what would you expect for tolerances on the bullet diameter? If they claim .401, what would be acceptable if you measured them?

In my case, I have some bullets I ordered and received for my 40 S&W that measure .4015 on my high end Harbor Freight calipers. The plunk test is real tight in my XD40 and depending on the brass, many don't pass. It's really close on most of them, as I have to push them in just a little.

So, I colored a particularly bad round with a sharpie, pushed in the round a few times, and found that the high spot on the brass is at the base of the inserted bullet. Back to the calipers I go, and I see that the base of the bullet seems to have the largest diameter in the few that I measured. These are coated bullets, so I wonder if the coating is just a little thicker at the base. I also wonder if they were never sized after coating.

Anyway, is .4015 too big in your opinion? I'll take humble opinions and all other kinds as well

Thanks!

 

[CMV]

Half a thou is very difficult to measure precisely.

If you go into a machine shop and have 5 different machinists (and I mean real machinists - not parts changers) measure the same feature, you're likely to have a small range of results. Especially if they don't know what it "should be" and they're just giving the number they got.

I have plenty of the HF digital calipers and for what they are I really like them. But just closing the jaws & hitting 'zero' isn't a guarantee of calibration. Sadly, I found that the 1" test blocks that come with them (and I have at least 8 of them) vary ±.002 so without a good calibration rod it's really hard to know how precise your gage is. And keep in mind they cost 10% of what a Mitutoyo does for a reason

Anyway, I would find ±.0005 from nominal perfectly acceptable. A sheet of standard printer paper is about .0035" so you're talking 1/7 of a sheet of paper thickness.

 

[Walkalong]

It should be fine. That doesn't mean that with thick brass and a tight chamber it might not have issues, but that would not be the norm IMO.

Besides, if it is the HF caliper that rounds to the nearest .0005, it could be .40128

 

[horseman1]

Thanks folks,

Walkalong, I neglected to mention that these babies are the HF old school dial version . I really had to use my old guy glasses to read that fine.

Actually, I went out and shot a couple magazines of them and the gun cycled fine. Just didn't pass the plunk test with flying colors is all

I don't like them not "falling in and out" of the chamber of the barrel. Seems like my XD40 may have a rather tight chamber and I should probably stick with jacketed bullets if I want high reliability and no failures to feed/eject.

Thanks for the help!

 

[Walkalong]

Have you loaded any .452 lead for this barrel?

 

[243winxb]

Xd40 40 s&w saami

SAAMI max is .4005" for the bullet. Chambers run .401" to .405" XD's seem to have tight chambers online. http://www.saami.org/PubResources/CC_Drawings/Pistol/40 SandW.pdf Double check your taper crimp.

 

[horseman1]

Thanks, I really appreciate the information.

I checked the crimp about 20 times with those high precision calipers . Got 20 different readins and took an average... No, just kidding. More crimp doesn't help. The brass is rubbing a little on the cylinder right where the bottom of the bullet is seated. I learned the sharpie marker test right here in THR. Been using it ever since. Takes some of the guesswork out of a plunk test failure for me.

 

[quaid]

A lee fcd would squish an oversize loaded lead round down. I did this with lasercast lead 45 in an xd. The lead was so hard a bullet not started perfectly straight would bulge one side of the case wall and prevent full chambering.

It's a bandaid fix but i didn't have to pull the rounds apart. I no longer use laser cast.

 

[Laphroaig]

Horseman,

I've only been loading cast bullets for 3 years, so am no way an expert. But this is what I've learned: 1) cast bullets have to be oversized to seal in the bore and prevent leading, and 2) some brass is thicker than others. The result is that some rounds end up being a little fat and don't plunk perfectly.

I started to dabble in Bullseye competition with my .45 and the experienced shooters/loaders indicated that is very normal. Ones that don't pass are designated as "practice ammo".

If they still function in your firearm I'd consider yourself fortunate and keep on loading them

Laphroaig

 

[LiveLife]

coated bullets ... The plunk test is real tight in my XD40 and depending on the brass ... The brass is rubbing ... right where the bottom of the bullet is seated.

Is the brass rubbing for a particular headstamp? If brass rubbing is happening on different headstamp cases, your problem may be with the bullet.

I have found bullets can be out of spec/round. Measure your bullet diameter not just once but several times at different locations. If the bullets were sized .401" before being coated and not afterwards, the coating will add to the diameter of the bullet. If your bullet is out of spec/round, it may definitely cause your finished rounds to not fully chamber. The only fix for out of spec/round bullets is resizing them so I would contact the bullet manufacturer. If the manufacturer is a reputable one, they should take care of the problem and send you properly sized (.401") bullets to you that are not out of round.

If the out of spec/round bullets is the root cause, as quaid posted, you could use the Lee Factory Crimp Die to post-size the finished rounds to fix the problem but I would test the neck tension so you don't experience too much bullet setback when the rounds are chambered. To test neck tension/bullet setback, feed dummy round (no powder/no primer) from magazine and release locked back slide without riding it. Measure OAL/COL before and after. With lead loads, I usually do not experience any bullet setback. If you measure more than a few thousandths, you may have neck tension issue from brass spring back that's causing bullet setback which will increase chamber pressure when the powder is ignited.

cast bullets have to be oversized to seal in the bore and prevent leading

If the bullet manufacturer advertised .401" sized bullets, they should be .401" and not out of round. I use .401" sized lead bullets from various manufacturers and I do not get leading in my barrels.

I started to dabble in Bullseye competition with my .45 and the experienced shooters/loaders indicated that is very normal. Ones that don't pass are designated as "practice ammo".

What if you decide to shoot USPSA/IDPA matches where stoppages will cost you critical stage times and score? For my match ammo, I used to test each finished round so they fell in the chamber with a "plonk/plunk" and fell out freely to ensure they would chamber fully during the match.

 

[Blue68f100]

Is this tied to one mfg of brass? if so look inside the brass and see if it has a ledge/step to prevent bullet set back. You may be setting your bullets too deep, too. Run the longest you gun will feed reliability.

 

[Laphroaig]

What if you decide to shoot USPSA/IDPA matches where stoppages will cost you critical stage times and score? For my match ammo, I used to test each finished round so they fell in the chamber with a "plonk/plunk" and fell out freely to ensure they would chamber fully during the match.

Bullseye has timed fire and rapid fire stages in which FTF will cost you points too. That's why we use "non-plunkers" for practice.

Laphroaig

 

[Lafitte]

I know you didn't ask about it but a Lee Factory Crimp die will fix the problem. It sizes the finished round thus taking care of different brass thicknesses and bullet diameter variations.

Lafitte

 

[LiveLife]

Bullseye has timed fire and rapid fire stages in which FTF will cost you points too. That's why we use "non-plunkers" for practice.

I understand the difference between bullseye vs action pistol matches. The point I was trying to make was what is acceptable to one reloader may not be acceptable to another reloader. If you are OK with out of spec/round bullets, that's your choice but not all of us should be expected to simply "put up" with out of spec/round bullets.

For me, if I paid for .401" sized bullets, I expect .401" sized bullets that are not out of round as anything larger/out of round will not work in my tighter Lone Wolf aftermarket barrels. And the OP is using a factory barrel, not aftermarket barrel, which are usually SAAMI+ chamber sizes. For a bullet to not work in a factory barrel, it would be quite a bit out of spec/round.

If the damage to the bullets were due to shipping/handling and no fault of the manufacturer, I would order from vendors that are self-insured (like Missouri Bullet Company) or offered insurance option (like Rocky Mountain Reloading) who would replace the damaged bullets at no cost.

 

[horseman1]

So, you guys deserve an answer about the brass/head stamp, so I had to do some work.

The success rate seems to be related to brass. I thought my R-P brass was the thinnest brass I had, but I might be wrong.

Winchester brass: 30 rounds out of 50 passed
Remington - Peters brass: 2 out of 20 passed.

The other thing I thought to mention is these bullets look beautifully made. I cannot say that they are out of round, or were damaged in any way in shipment.

I have a Lee FCD. I ran the ones through that would not chamber freely, but some still have a bit of friction. I even changed the FCD over to a bulge buster configuration and had the same results. This leads me to believe the chamber in the XD is pretty small and I probably should avoid lead/coated bullets for this gun.

What do you think?

 

[Walkalong]

You could always do a chamber cast if your feeling froggy.

http://www.midwayusa.com/product/462291/cerrosafe-chamber-casting-alloy-1-2-lb

I bought some cerrosafe and did my 300 BLK chamber. It was very easy.

 

[blarby]

Half a thou is very difficult to measure precisely.

Especially with a digital caliper that rounds up or down....... You get shunted to one extreme or the next based on pressure.

 

[gamestalker]

Is that an XDM?

I have two .40 cal. XDM's, and one XD, and those M's are definitely tighter chambers. I haven't had any issues loading for them, but I don't load lead either, so I can see how varying projectile sizes might cause such an issue.

GS

 

[Robert101]

My 2 cents worth of opinion is as follows: If the Lee FCD die does not work with this bullet I would change my bullet purchase. If I experienced similar problems with other bullets I would contact S&W explain the problem and see if they will replace the barrel with one that might be closer to the SAMMI specification as your existing barrel appears to be too tight. Does factory ammunition freely fall out of your barrel? You might be limited to jacketed bullets in this barrel.

 

[elwoodm]

i hate wondering what the problem is so get yourself a mitutoyo and then you will have no measuring issues. i agree neck and crimp check.

 

[horseman1]

Hi,

The gun is a Springfield Armory XD 40. So it's not the XDM, just the XD

I have used lead bullets in the past and have not had this type of problem. I suspect these bullets are a bit too large and my XD chamber runs on the small side. Seems like it's just a bad combination.

Elwood mentioning good calipers gave me an idea help reduce the probability that the calipers are the problem..

I went out to the shop and used the calipers to measure my other lead bullets and immediately measured the coated bullets I bought. It turns out the lead bullets were (according to these calipers) .001 smaller than the coated bullets and this was repeatable 100% of the time with 5 sample bullets of each. I would take a picture for you guys, but my flip cell phone wouldn't do a good job

Making my list for Santa:
Good Calipers
New cell phone
Casting equipment..

 

[horseman1]

Robert,

Factory loads work great. The 1200 other reloads I have made up with other bullets plunk just fine and work great. These actually shoot and cycle too, they just don't pass the plunk test and I know where on the brass they are sticking after coloring the round with a sharpie. I'll just watch which bullets I get for this gun in the future.

 

[LiveLife]

I have used lead bullets in the past and have not had this type of problem.

Ding Ding Ding! So we can rule out tight chamber barrel as the root cause. No need to contact Springfield customer service.

I went out to the shop and used the calipers to measure my other lead bullets and immediately measured the coated bullets I bought. It turns out the lead bullets were (according to these calipers) .001 smaller than the coated bullets and this was repeatable 100% of the time with 5 sample bullets of each.

Ding Ding Ding Ding Ding Ding! So the root cause of your finished rounds not fully chambering was out-of-spec/oversized coated lead bullets.

I started to dabble in Bullseye competition with my .45 and the experienced shooters/loaders indicated that is very normal. Ones that don't pass are designated as "practice ammo" ... That's why we use "non-plunkers" for practice.

Not normal in my book. Besides, if I shoot "action pistol" USPSA/IDPA matches, I want to practice double-taps not practice stoppage drills.

if I paid for .401" sized bullets, I expect .401" sized bullets

The only fix for out of spec/round bullets is resizing them so I would contact the bullet manufacturer. If the manufacturer is a reputable one, they should take care of the problem and send you properly sized (.401") bullets

As you indicated in your PM, I have not used that particular vendor's bullets (lead or coated) but I would suggest you contact that vendor and reference this thread. Based on the information posted on this thread, the vendor should realize oversized/out of spec coated lead bullets were sent to you and should offer to resize the bullets or send you replacement bullets that are properly sized at .401".

If the vendor refuses to help you, I would suggest you post the vendor's name so other THR members will know not to order coated lead bullets from the vendor and experience similar failure-to-fully chamber problems.

I have a suspicion these bullets were not resized after they were coated/baked.

BTW, Missouri Bullet Company sells Hi-Tek coated lead bullets (with 5% THR discount) and they are self-insured. If the bullets you receive are out-of-spec or out-of-round for any reason (even damage caused by rough handling during shipping), they will replace the bullets free of charge.

 

[mdi]

First off, I would suggest using plain old micrometers to measure the OD of your bullets. The thin and long blades of a caliper tend to cause "springing" of the jaws easily causing variations as much as .001" (life long machinist/mechanic and I never used a dial caliper for precise measurements of an OD, only micrometers). The machine shops that I worked in had inspectors and all machinists and inspectors were able to measure all parts within .0005" of each other...

I would consider "normal"/acceptable tolerances from a commercial caster to be -0.000" to +.0015" for mass produced lead bullets.

Also, I would suggest you continue to work on the problem rather than hiding/covering it up with a Lee FCD...

 

[LiveLife]

First off, I would suggest using plain old micrometers to measure the OD of your bullets.

Reloading is not rocket science and should not require the use of micrometers. For decades, bullseye match and 1000 yard bench rest shooters have used just calipers with excellent results. I am neither (just shot USPSA) and .001" resolution I get with Harbor Freight digital calipers work well to load 40S&W .401" sized lead bullets from Dardas/MBC/Z-Cast to fully chamber in tighter Lone Wolf barrels.

I would consider "normal"/acceptable tolerances from a commercial caster to be -0.000" to +.0015" for mass produced lead bullets.

No, not if other .401" sized lead bullets worked in OP's factory XD barrel. It is my opinion that these coated lead bullets are definitely oversized.

Also, I would suggest you continue to work on the problem rather than hiding/covering it up with a Lee FCD...

I absolutely agree. Identifying the root cause to eliminate the problem is the proper solution/best practice rather than using a bandaid temporary fix.