Author Topic: Polymer coated bullets  (Read 426 times)

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Offline NMShooter

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Polymer coated bullets
« on: March 23, 2020, 05:18:48 PM »
A few weeks ago I bought 2 sample packs of 9MM polymer coated hard cast bullets, 115 and 124 grain. I only received 25 bullets in each pack so I had to pick a powder, Silhouette for 115, and True Blue for the 124s, and hope for the best. The 115s at 5.5 and 5.7 grains showed real promise. The 124s not so much - with True Blue anyway. Both powders burned clean with True Blue being the cleanest. 25 rounds is not enough to really develop a load, I should have bought 100 of each. I shot these through my TSO. I'm going to clean the pistol today to see if there is any lead build up in the barrel. I seated a bullet, then removed it with an inertia hammer to see how the polymer coating held up, and there were spots where the coating did come off. I was as careful to watch for any of the coating building up on the case mouth when i seated them and did't see any. Hopefully the coating on the base of the bullet held up to the heat.
I also bought 500 .401 10MM bullets to test. I picked 4 powders one slow two medium and one fast burning powders: AA#9, Power Pistol, Blue Dot, and True Blue for the fast burner. I used True Blue because I'm hoping to find a load it shoots well. Its by far the cleanest burning powder I've ever used. I used a pretty good bell and chamfered the case mouth and still I saw some polymer and a little lead scrape off on 5 to 10 of the 10MM rounds when I seated them. I also used a moderate taper crimp on the 10MM rounds. 9MM no crimp just fed them into the mouth of the sizing die to flatten out the bell. I'd read somewhere the idea of using the sizing die to take out the bell, and it works pretty well. I don't have to reset my seater die as a result. I'll head to the mountains tomorrow to run the 10MM test. I'll post the results later.

Offline nicky

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Re: Polymer coated bullets
« Reply #1 on: March 23, 2020, 07:44:29 PM »
I was wondering. What does your crimp messure.

Offline Earl Keese

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Re: Polymer coated bullets
« Reply #2 on: March 23, 2020, 08:58:37 PM »
What is your purpose for these loads?

Offline Dan_69GTX

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Re: Polymer coated bullets
« Reply #3 on: March 24, 2020, 07:25:08 AM »
When using a kinetic hammer some coating can "scrape" off when the bullet bounces back and hits the case after the bullet dislodges from the case.  Looks more like a nick.

" I also used a moderate taper crimp on the 10MM".  Just remove the bell to make the case straight again. - same as 40 or 9mm or 45 ACP or....
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Online drband

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Re: Polymer coated bullets
« Reply #4 on: March 24, 2020, 09:13:12 AM »
I would encourage you to double check your sizing, flaring, seating, and crimp setups.  I use a lot of Hitek coated LSWCs and don't experience any scraping of the coating at any step.  Other bullets (FMJ, HP, plated) are more forgiving of slight problems with die adjustments.  I'm not saying yours are not adjusted properly-- just maybe need tweaking for the polymer coated bullets.

If you have loaded jacketed or plated, slight misadjustments may not even be noticeable.

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Offline lewmed

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Re: Polymer coated bullets
« Reply #5 on: March 24, 2020, 10:32:37 AM »
 I've been loading coated bullets from Bayou bullets for years and have coated many thousands of my own cast bullets with the Hi-tek coating.  I test my Hi-tek bullets by smashing a few with a 5 lb. hammer if the coating flakes off I did something wrong. The coating is easy to apply but the temp. has to be just right and for the correct length of time.

Offline NMShooter

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Re: Polymer coated bullets
« Reply #6 on: March 24, 2020, 12:02:27 PM »
Earl, the 10MM loads will be mostly practice, maybe woods carry. For hunting I lean towards the 200 Gr   XTP. The 9MM target, for the TSO and the SP-01.
Nicky, the crimp on the 10MM is .0015. There is no crimp on the 9MM.
I’ll check the seater setup. I trimmed just enough to assure the same cases length, chamfered,, then belled the case mouth. I noticed when I was seating, I could feel the groove on some of the 10MMs.

Offline 2morechains

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Re: Polymer coated bullets
« Reply #7 on: March 24, 2020, 06:28:50 PM »
If you’re seating and crimping with just one die, is your seating die a “taper crimp” or “roll crimp”? 

I load on a progressive press and have my seating die set so it just seats.  The die is backed off so no crimping takes place.  The crimp die I use is a taper crimp that is set to remove any belling with minimal crimping if any.  If I pull a bullet I don’t see any deformation or chipping of the coating (I use bullets with the Hitek coating).   

Offline NMShooter

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Re: Polymer coated bullets
« Reply #8 on: March 25, 2020, 02:52:41 AM »
I seat then crimp in two operations. I’m using a Redding micrometer seater die and have it backed off of the shell holder at least two turns I believe. I’ll give it another look tomorrow.

Offline SoCal

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Re: Polymer coated bullets
« Reply #9 on: March 25, 2020, 04:13:14 PM »
I seat then crimp in two operations. I’m using a Redding micrometer seater die and have it backed off of the shell holder at least two turns I believe. I’ll give it another look tomorrow.

I have had problems using my Redding micrometer die with coated bullets I went back to my Hornady.  I now only use the Redding with jacketed bullets.  You might try a different seating die.
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Offline NMShooter

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Re: Polymer coated bullets
« Reply #10 on: March 25, 2020, 09:48:00 PM »
Results 10MM Poly coated 180 Grain hard cast bullet. 34 degrees intermittent snow. i had loaded 10 at each weight and only shot 5 so I can verify the velocities when better weather permits. Shot from a rest from 25 yards. 

8.9 gr Power Pistol yielded the best group overall at 1.25" at 1225 fps Not sure if I trust this velocity as it was lower than the previous group 8.6 grains.

14.4 grains of AA#9 was close in accuracy at 1.5" but better velocity at 1342 fps.

I had cleaned and dried out the crono after the Power Pistol test and I think this velocity is pretty accurate.
 
True Blue and Blue Dot didn't produce any satisfactory groups.
 
I inspected the bore with a borescope after 100 rounds of the Polymer coated bullets and it was surprisingly clean, no leading observed. I cleaned the barrel, again no lead.
I'll probably use the AA#9 for my woods carry load and use the Power Point for target, which works out pretty well as the #9 load uses 60% more powder.

 

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