Does lube in the barrel swage fired cast bullets to a smaller diameter?

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joeb33050 posted this 06 August 2019

 

 

 

I don’t think so.

 

I’ve seen thousands of cast bullets in the berm with lotsa lube in the grooves.

 

I’ve never seen any lube in barrels while cleaning them, only black stuff and not a lot of volume of that.

 

I think any lube in the barrel is scraped out by the next bullet.

 

I’ve got a .22 barrel and bullets ready for the believer/experimenter. Lube up the barrel, push bullets through, measure them and find out for sure.

joe b.

 

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Ross Smith posted this 06 August 2019

Joe , I have a bunch of bulk white label red 2700+ if you want it for testing.

Ross

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joeb33050 posted this 07 August 2019

Ross;

I'm not doing the testing, but have a .223 barrel to donate to a tester. Lube the barrel, push the bullet through, see if its smaller.

Any diameter reduction is caused by the sawdust friction scraping lead off.

joe b.

 

 

Joe , I have a bunch of bulk white label red 2700+ if you want it for testing.

Ross

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Ken Campbell Iowa posted this 07 August 2019

joeb likes math, so check this out:

(  car bottle jack force of 4000 pounds ) / ( area of 30 cal lead bullet of 0.1 sq. inch ) = 40000 psi at base of bullet in a tight sizing die.  would the magic happen ? 

hey, we wouldn't have to ride a fast horse to catch the molested bullet ... just have to get it out of the die ... hmmm ...

should the sizing die be a length of rifled barrel ?  or just a polished steel straight groove diameter bore ? 

*************

... and is there any merit to the above scheme ?? ... after all, it is way early for me to be thinking good ..

ken

 

 

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joeb33050 posted this 07 August 2019

It's the sawdust. We can't capture a fired bullet without damaging it.

.308" dia ~.075 in * in

1/.075 ~ 13.42

13.42 * 4000 ~ 53687 psi

But, it's the sawdust.

Where are the testers?

 

 

 

 

 

 

 

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Larry Gibson posted this 07 August 2019

I didn't use sawdust.  Also on another forum a poster recovered 44 bullets shot into snow and found they were reduced in diameter less than the .429 of his slugged barrel. 

As posted on the other thread concerning this subject;

"Those "very low end pressures in 1000+/- fps loads " still had sufficient pressure to obturate the softer alloys used for those loads......just as RicinYakima points out.

Pushing a bullets, lubed or not, through bore is basically what we call "slugging the bore"  The results are not going to be the same as shooting the  bullet through the bore with a 20,000 psi load behind it. Or as in the bullets I recovered, 50,000 psi."

I would think if one is to test to refute what has been posted one should attempt to replicate the test........if for no other reason than to assure the results did or did not happen that way?

LMG

Concealment is not cover.........

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45 2.1 posted this 07 August 2019


I would think if one is to test to refute what has been posted one should attempt to replicate the test........if for no other reason than to assure the results did or did not happen that way?

LMG

 

That sounds good Larry.... but it's your post and  you are the only one who knows what you did. A summary of what firearm and load parameters data as per the CBA match requirements would help anyone who wishes to duplicate the load. The 1000 +/- fps load would be fine assuming no one wants to play with the full bore one. Recovering a slow bullet is MUCH easier than and fast one.

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Ross Smith posted this 08 August 2019

Not an expert, not at all. Curious, can heat be playing a role? The gun powder produces a lot of heat and so does friction in the barrel. Lead wants to expand but is swaged by the barrel to barrel dimensions, then cools after coming to a rest. Then shrinks a tiny little as it cools?????????????????/      Any merit?

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John Alexander posted this 08 August 2019

Ross,

Excellent! Maybe you are an expert. 

I think that is a much more promising mechanism to explore than any I have heard so far.  The numbers would be simple to run if we had an estimate of the temperature of the bullet when it leave the muzzle.  I'll bet the Army knows the temperature of jacketed bullets which must be similar. Jacketed bullets would spring back but not lead.  

I am betting this is the answer to the puzzle.

John

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Paul Pollard posted this 08 August 2019

There seems to be several threads going on about bullet diameter reduction. I have not recovered bullets which have been shot. I don't have too much data. Several years ago when processing 6mm bullets, I noticed something strange with the size after lubing and bumping the bullet in separate presses.

My spring-loaded gas check seater press kept sticking and would not eject the bullet. My solution was to add lube and then add more lube before seating the gas check. After lubing in a lubesizer, then bumping (swaging), the bullet was smaller diameter than expected. I finally worked backwards and forwards to find that the excess lube was causing the bullet to be sized smaller in diameter. After enlarging the gas check seater die at the base where the gas check entered, the bullet would eject without adding any lube. Problem solved.

Several days ago, with a 30 caliber bullet, a very heavy lube which requires heat, did the same thing when sizing and tapering.

This leads me to believe that excess lube can be a bad thing. Maybe excess "low viscosity" lube would not be a bad thing.  I don't what happens in a barrel when shot.

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Larry Gibson posted this 08 August 2019

 

That sounds good Larry.... but it's your post and  you are the only one who knows what you did. A summary of what firearm and load parameters data as per the CBA match requirements would help anyone who wishes to duplicate the load. The 1000 +/- fps load would be fine assuming no one wants to play with the full bore one. Recovering a slow bullet is MUCH easier than and fast one.

 

 

 

Well, 45 2.1, my test was in conjunction with the 30x60 XCB cartridge with the 30 XCB bullet at 2900 fps.  As to the lower end velocity tests, that was conducted by goodsteel.  Not sure he posts here as he has his own forum.  You could ask him there for his test results and procedures.  As to mine I shall endeavor to reconstruct the test here but keep in mind, according to the dates on the photos, the test was conducted on 8 January, 2016.  The photos were converted to png format on 11 January, 2016 so that is probably when I posted the results here. 

 

 

 

I previously asked about a search engine for this forum but received no answer so I cant find the original post.  Thus I am reconstructing the details and results of the test from memory and Ive conducted a lot of other tests since then.  So if this post differs in any way from the original, should you or anyone else find it, I shall default to the original post for any corrections.   

 

 

 

The intent of the post was to determine the suitability of the WQAlloys penetration and expansion at a probable maximum range for use on deer.  Given moa accuracy had been proven with the ternary alloy 30 XCB cast bullet at 2900 fps I received additional criticism and conjecture that the bullet would fragment at any reasonable hunting distance on game because I had stated it should be effective to 300+ yards because the retained velocity at 300 yards was 1900+ fps.  The purpose of the test was to determine the terminal performance potential of the bullets at longer range. 

 

 

 

To trap the bullets with minimal damage I chose to use soggy wet newsprint. Previous tests with that medium proved it gave expansion to cast bullets.  Thus I collected a bundle of news print and used target about 18 in depth.  Those were placed in a plastic garbage bag (to retain the water), placed in a cardboard box and then thoroughly soaked for several days prior to the test.  At my local range (Sarah Park, Lake Havasu, Az) the newsprint bundle/box was palace at the 300 yard line.

 

 

 

At the firing line with solid cent benches I set up the rifle.  It was my 30x60 XCB barreled and chambered by goodsteel to the 30x60 XCB cartridge.  The barrel is a Broughton 31 Palma contoured stainless with 3 grooves with a measured bore of (Broughton) of .3077x.3003.  Goodsteel also measured it confirming those dimensions.  When I received the rifle I slugged the bore for groove diameter and came measured 3 different slugs at .3076.  I pin gauged the bore and a .300 pin would go in but a .301 would not.  The barrel was put on a CZ24 M98 action which I bedded into a Carlson Premier stock.  The rifle has a Leupold 6.5x20 target scope on it. 

 

The test rifle;

Concealment is not cover.........

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Larry Gibson posted this 08 August 2019

 

The test load in the 30x60 rifle was the same 2900 fps load that I’ve posted about numerous times on this forum.  I have demonstrated numerous times and posted on this forum, including many pictures, the moa capability of the rifle, the cartridge and the cast 30 XCB bullet out to 600 yards.  Others have shot this rifle/load at 300 yards and attested to its ability on the CBF forum.   The bullet, as mentioned was the 30 XCB cast of #2 alloy, WQ’d, weight sorted, sized at .3105, GC’d with a Hornady GC and lubed with 2500+.  The 30x60 XCB cases were Winchester (formed from ’06 cases) with necks turned to fit the tight XCB chamber neck.  Primers were WLRs.  AA4350 was used with 53 gr giving 48-50,000 measured psi.  Muzzle velocity runs 2900 – 2910 fps. 

 

 

 

The test;

 

 

 

An 8x11” target was placed on the front of the box of newsprint at 300 yards with a 1” paster in the center.  I shot 5 shots intending thinking the wind would spread the rounds out as it was a bit blustery so I did not quite succeed with that.  As it turned out the first 5 shots went into 2.19” at 300 yards.  I noticed one shot (#5) on impact blew out the side of the box and impact in the so I adjusted the scope up and right ¾ moa and shot a 6th shot to have 5 shots recoverable.  I should have shot a 7th as it was found that one bullet (of the two touching on the target; #4 & 3) hit the other bullet in the drive band area damaging it.  Had I not made that sight adjustment the 6th shot would still have been within the sub moa group at 300 yards.

Concealment is not cover.........

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Larry Gibson posted this 08 August 2019

 

The impact of the 6 bullets imparted considerable energy into the box/bundle.  The box burst and the bundle elongated to approximately 28”.

 

 

At 1900 fps impact a considerable amount of terminal damage was still done.

 

Concealment is not cover.........

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Larry Gibson posted this 08 August 2019

 

The five bullets that stayed in the newsprint were recovered.  Two still retained the GCs and two of the three shed GCs were recovered. 

 

 

 

Above we can see from the recovered bullets they did not shatter as was claimed.  There was actually some expansion even though they had been Wq’d  with a BHN of 20 – 22.  The two left bullets are the two that collided in the newsprint.  The nose of one (the right of the two) was damaged and the drive band area of the other (left one) was damaged.

 

 

 

Here we see the noses of all five recovered bullets.

 

Concealment is not cover.........

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Larry Gibson posted this 08 August 2019

Here we see the damaged bullet;

 

 

 

There appeared to be some evidence of gas cutting or?  But then at 2900 fps under 48-50,000 psi with a naked lubed ternary alloy cast bullet……?

 

 

Concealment is not cover.........

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Larry Gibson posted this 08 August 2019

 

It was on close examination of the recovered bullets I noticed all the bullets, including the impacted one, had good uniform diameters in the drive band areas.  Any expansion had been in the nose area only and none of the bullets exhibited and impact expansion in the drive band area.  None of the bullets showed any indication of erosion of the sides by the test media.  I thought I would get a very good measurement of the true groove diameter as compared to slugging the bore. 

I was quite astonished when the micrometer measurement (yes it has been “calibrated” and measures accurately) showed the drive

band area (undamaged) from all 5 recovered bullets ran .003 to .005 under the groove diameter of the barrel. 

 

 

 

I mentioned that on the CBF forum and goodsteel and Lars then built their bullet trap and conducted their tests.  They had the same results; naked lubed cast bullets they recovered all were smaller than the groove diameter of the test firearms.  They also concluded it was the film of lube the bullets had to ride on (after all that’s what keeps them from leading) that was swaging the bullets to the smaller diameter.

 

 

 

So, there’s the results of the test I conducted and the results.  Again it’s as best as I recall them so if there’s a discrepancy between this and the original posts I default to the original as correct.

 

 

 

Now, 45 2.1, you often mention shooting into a hillside at some distance so you should be able to replicate this test easily enough with any of your own HV 2400 +/- loads using a ternary lubed cast bullet.  If you have PC’d bullets you might also try those as it would be interesting to see their recovered diameters as compared to the naked lubed cast bullet diameters. 

 

 

 

LMG 

 

Concealment is not cover.........

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TRKakaCatWhisperer posted this 08 August 2019

Let me raise the question of how fast the bullet stopped?  Hence, what distortion took place and where.  It appears to me that if the nose mushrooms out that it might-could be that the material in the back of the bullet moved slightly forward (reducing the OD at the back).

One way to test this is to duplicate Mann's recovering of bullets in the winter.  I did something similar 50 years ago when out shooting on the frozen river.  The bullets would slow down VERY gradually - encountering little rifts of snow and stopping in 10-20 yards - with ice crystals encrusted on them but otherwise in perfect shape.

Just thinkin' ...

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Larry Gibson posted this 08 August 2019

A fellow posted on the CBF forum that his M29 had a slugged .429 barrel and he recovered some bullets out of snow (?) and they were also .003 - .005 less diameter than that.  I don't have a lot of snow here where I live in Arizona so I'll leave that testing to some one that has a lot of snow.

LMG

Concealment is not cover.........

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45 2.1 posted this 08 August 2019

 

I was quite astonished when the micrometer measurement (yes it has been “calibrated” and measures accurately) showed the drive band area (undamaged) from all 5 recovered bullets ran .003 to .005 under the groove diameter of the barrel. 

 

You gave a range, Goodsteel showed what each band measured in relation to the groove diameter. What were yours so we can compare it to Goodsteels.

 

Now, 45 2.1, you often mention shooting into a hillside at some distance so you should be able to replicate this test easily enough with any of your own HV 2400 +/- loads using a ternary lubed cast bullet. 

 

My hillside trap is at about 400 yards and is not usable part of the year due to greenery in the way, but it is powdered dryish glacial till (it is a mottled clay laid down from glacial activity in this area). I know that material well as I've built several FAS roadways from it in the last 30 years. I've tested that trap at that distance with very soft alloys to see if it expands bullets when fired into it. It doesn't. In fact I've done this test many times. Several, including the last one involved air cooled and water dropped bullets cast at the same time and aged several weeks till they were stable in hardness. That bullet was the 30 Sil at about 2400+ fps in an 18" barrel out of a 308. Those would have been going close to your test speed in a 31" barrel like you were using if I had used one. I also used my own low viscosity lube. The air cooled bullets were slightly scuffed and the nose was bumped to show full land engraving  to the nose ogive. The water dropped bullet noses didn't bump and all the pertinent surfaces the grooves touched measured as normal groove diameter on all bullets of either hardness out of that barrel. Since there is a despairigy in results, something either in materials or method is causing it. Someone else needs to try..........................

 

 

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Larry Gibson posted this 08 August 2019

45 2.1

I ran that test over 3 years ago.  If I saved the bullets it is very doubtful given all the tests I conduct.  If I saved all the targets, bullets etc. to document question 3 years later I wouldn't have room nor the time to do anything else. Mostly I document via picture these days and hard copies of past article/tests I've conducted.   It is unfortunate I am unable to find the original post but it's been reconstructed for you. However, I do still have the micrometer I measured the recovered bullets with and as you see (picture just taken for your benefit) it is not a blade micrometer.  In measuring the diameter at the drive bands it covers all three in the same measurement. 

[Note; the 30 XCB measured is a cull to be used as a fouler.  It has a slight pin hole forward of the leade taper slightly to the right.]

As to the differences in alloys and lubes between my test and your test making any difference I believe a close reading of goodsteels posts and taking note of will reveal he and Lars used a different alloy (softer with lower BHN) than I used and since Lars makes some very fine lubes they also tested different lubes.  They also tested in different cartridges with different twists and maybe even a different caliber (?).  Their velocities were also lower than mine closer to yours.  Yet their results in measuring the recovered bullet diameter were the same as mine in every test they conducted. 

If you have a blade micrometer could you measure the diameter of each drive band of your recovered bullets?

I think your right, someone else, without a dog in this fight so to speak, should test....... 

LMG

Concealment is not cover.........

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45 2.1 posted this 08 August 2019

45 2.1

I ran that test over 3 years ago.  If I saved the bullets it is very doubtful given all the tests I conduct.  If I saved all the targets, bullets etc. to document question 3 years later I wouldn't have room nor the time to do anything else. Mostly I document via picture these days and hard copies of past article/tests I've conducted.   It is unfortunate I am unable to find the original post but it's been reconstructed for you. However, I do still have the micrometer I measured the recovered bullets with and as you see (picture just taken for your benefit) it is not a blade micrometer.  In measuring the diameter at the drive bands it covers all three in the same measurement. 

[Note; the 30 XCB measured is a cull to be used as a fouler.  It has a slight pin hole forward of the leade taper slightly to the right.]

As to the differences in alloys and lubes between my test and your test making any difference I believe a close reading of goodsteels posts and taking note of will reveal he and Lars used a different alloy (softer with lower BHN) than I used and since Lars makes some very fine lubes they also tested different lubes.  They also tested in different cartridges with different twists and maybe even a different caliber (?).  Their velocities were also lower than mine closer to yours.  Yet their results in measuring the recovered bullet diameter were the same as mine in every test they conducted. 

If you have a blade micrometer could you measure the diameter of each drive band of your recovered bullets?

I think your right, someone else, without a dog in this fight so to speak, should test....... 

LMG

Larry, you posted this before:

At the firing line with solid cent benches I set up the rifle.  It was my 30x60 XCB barreled and chambered by goodsteel to the 30x60 XCB cartridge.  The barrel is a Broughton 31 Palma contoured stainless with 3 grooves with a measured bore of (Broughton) of .3077x.3003.  Goodsteel also measured it confirming those dimensions.  When I received the rifle I slugged the bore for groove diameter and came measured 3 different slugs at .3076.  I pin gauged the bore and a .300 pin would go in but a .301 would not.  The barrel was put on a CZ24 M98 action which I bedded into a Carlson Premier stock.  The rifle has a Leupold 6.5x20 target scope on it. 

 

Now you show the mic you used without appending notes.

I think possibly I see what the whole problem is!

Odd groove barrel slugs can't be measured normally (as any barrel maker can tell you).  Measuring with a standard micrometer gives a smaller measurement. You've stated is was a three groove barrel which requires a specialized measuring tool.

 

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