Bullet Consistency

[Deleted]

I'm a believer (whether right or wrong)in the thought that bullet/barrel fit and loading force/pressure consistency plays a role in accuracy shooting sabotless, and I know sizing takes that factor to a minimum but there are those land rider shooters out there like myself who may find this interesting, and I was bored and curious, so...

I took the time to measure some different bullets for consistency, I was doing this for my own sake of grace, but I found it to be interesting and quite frankly, surprising. So I figured I'd share my results with everyone. This was done with a digital micrometer and it was done wherever the bullet first landed between the micrometer (because as you turn or rotate the bullet, you get different readings) So I didn't want the test to be biased. Here are some of my results:

240 CEB: .39965, .39970, .39985, .39970, .39970, .39975 (Deviation - .20)

300 MH's: .45090, .45115, .45065, .45080, .45070, .45100 (Deviation - .50)

275 Barnes XPB: .45040, .45065, .45080, .45075, .45045, .45050 (Deviation - .40)

300 SST: .45185, .45195, .45185, .45195, .45195, .45180 (Deviation - .15)

I do have some other bullets I could check as well if anyone was interested, ( 200 SST, 200 FTX, 225 FTX, 195 Barnes, 250 TEZ's, 250 SST, 250 FTX, 275 MH's)
Sorry if I bored ya to death with all this hubub, and I know this and a $1.25 will get a cup of coffee at McDonalds, I just thought it was interesting and maybe it would help someone that was experiencing different loading pressures understand maybe why.

[hankinsrfls]

Ohio guy...

If you told me you were getting different measurements from swaged bullets I could understand the slight differences,,,, But the CEB is cnc lathe turned and should be able to hold zero tolerances for out of round. I have been measuring to the tenths most of my life and you will get a variance just by using a different pressure on the micrometer. A few tenths is normal. You would never see this with a standard Micrometer but the new digital mics will measure much more accurately so therefor the slightest difference will read differently. Just holding the bullet at a different angle will give different readings.
Also I think you meant to add two zeros in front of your numbers because .20 is really read as two hundred thousandths and I am sure you meant to say two tenths of one thousandths. .0002,,,, .0005 being a 1/2 thousandth and .015 being a thousandth and a half.

Bullets are not perfectly round but I don't think a thousandth .001 or so will hurt anything as for accuracy... IMO.. Jeff.

[Deleted]

I like this test and I have noticed different loading pressures in the MH and I feel it could cause issues however when you fire your rifle and the bullet swells into the rifle I'm not sure how much it really affects your groups.

I ordered a sizing die and as soon as I get it I might be able to see how much difference there could be. I feel the closer the diameters are in each bullet the better your groups should be, one more variable taken out of the equation.

Good test in my opinion.

[Deleted]

Jeff you are correct, I did leave out a digit, I didn't catch it til after the fact, thanks for pointing that out. I sat my mic flat on a bench and set the bullet in each time and.didnt touch it again til I was done and did my best to get a reading at very first contact every time, I tried to be exact thru the whole process, best I could so the outcome was as accurate as I could make it. I know there will always be some variances, I guess I was just most shocked that the 300 SST was the truest of all that I checked.
Thanks for your input Jeff, hey for giggles, when you get a chance could you do the same test on the BE's? I don't have any but would love to see what they run. Thanks
Guy

[hankinsrfls]

I have checked them before and they will vary some. Here are the measurements I get as I rotate the BE around in four different places at the base of the bullet... .45175, .45180, .45175, .45175,, if I go up the bullet half way the measurements are,, .45100, .45110, .45080, .45095 and if I go up just to the ogive it is,,, .45080, .45105, .45070, .45075. The variance is small but it is there.. It does show a little out of round but I don't think it is enough to worry about.. Swaging them will or should help make them more round, unless your swager if out of round and then it will make them worse.. Jeff.

[Deleted]

Thanks Jeff. I still plan to get my drop to you so this topic will no longer be an issue for me..
Not that it was the end of the world anyhow, but I'll feel better knowing its a non issue.. One less item to think or worry about.

[jims]

IMO for the most part those tolerances are pretty small. I often wonder after, especially in a centerfire, when the bullet engages the rifling at the pressure, speed and heat imvolved how much the bullet might get distorted.

[hankinsrfls]

It takes on the exact shape of the inside of your bore. In a center fire rifle that is. In a SML it is a little different. If your are shooting smooth bullets, you need a bullet soft enough to swell and enough pressure to make it swell. That harder the bullet the harder this is to get to happen. That's when full forming comes into play. It helps fill the groves so that not as much pressure is needed to swell the bullet. Even the 451's can benefit from full forming if your barrel is truly a .450 bore.

[lwh723]

I think the biggest issue with bullet size variation in SML is how it changes ignition characteristics. We've definitely seen duplex loads help to over come this, but now with the 0.040" orifice flame throwers, I suspect this will be less of an issue. Earnhardt did some great testing to show that velocity didn't change much even as he varied the fit of the bullet. Likely, I'll still push bullets (smooth and FF) through the die 3X for maximum size consistency as more consistency certainly won't hurt anything, but

Jeff, certainly, you've experienced some tight an loose fitting bullets when shooting groups you with your guns, have you seen that generate fliers/velocity swings?

[Deleted]

Aug 26, 2014 22:48:27 GMT -5 lwh723 said:

I think the biggest issue with bullet size variation in SML is how it changes ignition characteristics. We've definitely seen duplex loads help to over come this, but now with the 0.040" orifice flame throwers, I suspect this will be less of an issue. Earnhardt did some great testing to show that velocity didn't change much even as he varied the fit of the bullet. Likely, I'll still push bullets (smooth and FF) through the die 3X for maximum size consistency as more consistency certainly won't hurt anything, but

Jeff, certainly, you've experienced some tight an loose fitting bullets when shooting groups you with your guns, have you seen that generate fliers/velocity swings?

Being that you brought up the .o40 orfice do you feel you could get away with a single load rather than a duplex using the 209 primers? Zen and i are looking at getting the tungsten bushing and are unsure on which one to get. .o30 vs .o40

[lwh723]

Aug 26, 2014 23:11:58 GMT -5 @78riverrat said:

Aug 26, 2014 22:48:27 GMT -5 lwh723 said:

I think the biggest issue with bullet size variation in SML is how it changes ignition characteristics. We've definitely seen duplex loads help to over come this, but now with the 0.040" orifice flame throwers, I suspect this will be less of an issue. Earnhardt did some great testing to show that velocity didn't change much even as he varied the fit of the bullet. Likely, I'll still push bullets (smooth and FF) through the die 3X for maximum size consistency as more consistency certainly won't hurt anything, but

Jeff, certainly, you've experienced some tight an loose fitting bullets when shooting groups you with your guns, have you seen that generate fliers/velocity swings?

Being that you brought up the .o40 orfice do you feel you could get away with a single load rather than a duplex using the 209 primers? Zen and i are looking at getting the tungsten bushing and are unsure on which one to get. .o30 vs .o40

Using the 310apb ff with medium pressure I only saw about 80 fps velocity loss with a single powder and a 030 vent going from 80F to -15F last winter. I would be very confident that the 0.040" is going to easily light a single no matter the temp.

[Jon]

Very interesting thank you.

[rangeball]

Aug 26, 2014 23:11:58 GMT -5 @78riverrat said:

Being that you brought up the .o40 orfice do you feel you could get away with a single load rather than a duplex using the 209 primers? Zen and i are looking at getting the tungsten bushing and are unsure on which one to get. .o30 vs .o40

I'm planning to go with the .040. Not yet sure if I'll stay with a single or go with the AA5744/H4198 duplex with the 310 APB.

[rangeball]

Aug 26, 2014 23:33:47 GMT -5 lwh723 said:

Using the 310apb ff with medium pressure I only saw about 80 fps velocity loss with a single powder and a 030 vent going from 80F to -15F last winter. I would be very confident that the 0.040" is going to easily light a single no matter the temp.

Luke, are you planning to test the .040 bushing the same way to see if you can eliminate this fps swing with a single?

[lwh723]

Aug 27, 2014 8:37:39 GMT -5 rangeball said:

Aug 26, 2014 23:33:47 GMT -5 lwh723 said:

Using the 310apb ff with medium pressure I only saw about 80 fps velocity loss with a single powder and a 030 vent going from 80F to -15F last winter. I would be very confident that the 0.040" is going to easily light a single no matter the temp.

Luke, are you planning to test the .040 bushing the same way to see if you can eliminate this fps swing with a single?

I hope not. I had enough of the -15 to -30 weather last winter. But yeah, I'll do more cold weather testing. I assume there will still be a drop, but hopefully not as pronounced.

[edge]

IMO, Ignition can play a significant role in bullet shape!

Lets say you use a smooth sized bullet.
Clearly the bullet does NOT fit the grooves at the moment of ignition so what fits there?
Gasses, particles of powder and products of ignition right?

Gasses can be expelled and replaced by bullet, but what about the hard things?
The bullet takes their shape and becomes destabilized ( by a minute amount).
What about a fouled bore buildup, does it help or hurt?

Back to the original point, you will almost always find the largest diameter of a bullet at the pressure ring at the base or the junction of shank to boat tail.

edge.

[rossman40]

There is a benchrest guy that uses something like a MRI/ultrasound to check bullets for anomalies in the jackets. There was another that was spinning them up in a jig to check balance. Making a uniform jacket "cup" is the key. Berger makes more money selling just the J4 jackets to other bullet makers then they do selling bullets. Supposedly there is a new process that Hornady started using a couple of years ago that makes a extremely uniform cup. Even with a good cup you still have to get the lead core in with no air pockets and then swag the nose. That's why for ultimate accuracy long range the turned monos have the edge.

[hankinsrfls]

Aug 26, 2014 22:48:27 GMT -5 lwh723 said:

  Luke.

 I have tested rifles with loos bullets and some with tight fitting bullets and I really have not found it makes a lot of difference in accuracy. I use mostly the BE's so that might be partly why I see no difference. As for velocity. I rarely check a rifle for velocity. Accuracy is what I am looking for when test firing a new rifle.  I have tested the velocity on my SML, and on 90 degree days I will get just at 3000 FPS and on a -4 degree day I was averaging 2953. To me a 50 FPS difference is not enough to be concerned about, especially out to 3-400 yords. That is most likely the farthest shot most of us will ever take uness we set ourself up for a longer shot and then we should be more prepared for that long shot. There is just so many variables to this game that it is hard to pin point all the possibilities. Jeff

[edge]

Vern Juenke comes to mind when talking about bullet concentricity machines.

edge.

[Richard]

No, Vern Juneke comes to mind with measuring the wall thickness or whatever type of readings the instrument does. For a while they were the rage of the short range BR crowd but bullets separated by various readings (it never came down to ten thousandth of an inch.....it was some other type of reading. The former president of IBS, Bob White, who I shot with regularly when I live up in NJ, had one. He told me he had a batch of bullets separated into three categories and was never able to tell the difference? Others said it worked? Bob was a pretty sharp guy and good gunsmith so who knows. But Rossman is right. it depends on the wall thickness and the quality of the lead cores and how they are installed and pointed. So far, in the 600 yard BR game I have not heard of anyone using CNC turned bullets..............still cup and core! Most everyone Berger's.
Richard

[rossman40]

Used to be long range was 1000yds. Then with the .50s and .338 LMs it got stretched to a mile pretty quick. Now with the hot rod .375s, .408s and .416s you have matches out to 2000-2500yds.

[7mmfreak]

1000m is still a long ways

[Richard]

The problem is finding a place on private land to shoot that far, especially in the eastern half of the USA. I shot at Tom Sarver's Thunder Valley in Ohio (1680 yards) when he first got it done and hit that 4' gong a few times. But, my 6.5 was a bit too light and the wind really played heck with it. Plus, I had some 30 moa in the mount and still had to use my 6 - 24 Valdata scope at 17X go to the very bottom post (below the mil dots) to get enough elevation for a 147 gr. bullet at 2900 fps to hit that thing!
Richard

[7mmfreak]

Yeah, the only place I have shot past 1000m in NC is Ft Bragg and Woody's in Fuquay. I'm not sure if there are many other options. There are a couple places in GA that host Mammoth Match but I lived in GA for 5 years without many places to shoot.

The options back home in TX are a little better. Nothing is better than living out west near BLM land tho. There are better PRS match opportunities out west too.

[yule]

7mmfreak

There is a 1000 yard range in Wilkes co. ( between Wilkesboro and Boone) - Hawk Ridge.

[edge]

What is kind of weird is that if you look inside the meplat of a Berger or SMK the lead is not consistent at all!
They go to extremes to get the jacket perfect and then let the lead flow wherever.

edge.

[7mmfreak]

Aug 28, 2014 7:15:00 GMT -5 yule said:

7mmfreak

There is a 1000 yard range in Wilkes co. ( between Wilkesboro and Boone) - Hawk Ridge.

Yeah, I knew Hawk Ridge was out there but haven't shot there. Camp Butner is available also if you have a RFMSS account, when North State hosts a match, or if your gun club has $1,000,000/incident insurance policy but it only has 1000yds KD and about 850m UKD. Jejune runs 1000yds matches too but only open to civilians for sanctioned matches. My club has access to the 1000m KD range on Bragg on the weekends but only for practice. Bragg is too big a pain to deal with to run matches beside the fact that there are several other well established venues. The range also faces east. The Piedmont Gun Club range only goes to 600yds I think.

There just aren't many places for field fire past 1000m. Woody's in the only one I am aware of and it was match or practice days only until a few months ago and now it is available as a private club but the fees are high. It's also a haul from my house. So, I stick with my club range to 300yds and then shoot the KD range on Bragg on the weekend. Lejune, Woody's, and Butner are all reasonable day trips for a match.

Is Hawk Ridge just IBS matches?

[yule]

Not sure. I just know it where it is. Never shot there.