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Plated bullets and crimp....


DougCarden

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Here is the results of some experimentation I did with the 38 short colt round and WCB 147RN bullets.

My Goal- find a load around a 130PF load for steel with some accuracy at 25yds, that way the tight 6-8in. plates wont be a question mark for me at speed on the course of fire. I also wanted to try the RN design as You have to do standing static loads for some of the Courses of Fire.

Gun is SW 627 with custom 6.5in bbl (dia is .3565) comped and Cmore 4moa

I know that due to the length of the cylinder charge hole the bullet has a ways to go before it hits the forcing cone, but I am stubborn and had some time to play with it.

My old load of a .357 125jhp with a small amount of CLAYS works well, but on a hot day extraction can be a problem, and I was getting around 3in. at 25yds with it.

I then tried to experiment with crimp as well to see what it did to the loads, since the conventional wisdom with plated bullets is to crimp litely due to base deformation leading to accuracy loss. Here are the results: :ph34r:

Crimp .374 .372 .370

3.0gr CLAYS 2.984 6.300 4.60

3.0gr VV310 3.6 3.128 2.588

3.4gr Titegroup 4.544 3.2 5.620

3.0gr N100 4.528 3.271 2.535

4.2gr WAP 3.144 4.105 3.520

So far the winner is the VV310 at .370, second is the N100 at .370. What am I going to do now is try the VV310 and N100 with more crimp, .368-.369 and see where the accuracy drop off is. The VV310 load is just fine, and I was able to knock down a popper at 35yds with a low hit, so It will work and do what I need.

I initially started the crimp and pulled bullets until I found the crimp that didnt mark the bullet, at .374 and going farther down it does mark the bullet more by the crimp. I dont think the crimp deformation is hurting the accuracy at this point, and I know that I am limiting myself by my powder choices, but I like the felt recoil of the big bullet/fast powder, plus it is what I have on hand ;) I load WCB in .40 for match loads and .45 for 625 REVO loads, and the less crimp the better as far as accuracy goes in those calibers. What did this teach me.......You gotta take the time and find what works well in your gun, these loads might not group as well in stock bbl. guns, but who knows. These loads are not chronoed(my chrono was taken out by an errant gas check, and I havent got it fixed yet.... :wacko: ),but safe in my gun with Federal small pistol primers. REDUCE loads by 10% in your guns for safety. Hope somebody learns something from this, as I am still digesting it as well. And yes, I know accuracy would be possibly better with jacketed bullets, but wanted to see what I could do with the 147RN design. Be safe, DougC

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Guest Larry Cazes

Contrary to popular wisdom of a very light crimp on plated bullets, my experience in .45acp and .40SW is similiar to yours. If I use a very light crimp which just barely removes all of the case flare but doesn't mark the bullet, my accuracy is not the best. I have to go about .002 to .004 past removing the flare depending on the load to get the best accuracy. This amount of crimp definitely marks/deforms the bullet slightly. I have been using plated west coast bullets exclusively for the last 3 years with excellent results. :D

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That's been my experience as well with .40(short) and 38super. I usually crimp about .003" because the accuracy has never been better with less than that.

YMMV

PS - make sure you shoot groups with all the same brand casings or you're most likely wasting your time. One brand will shoot just as accurate as another for me, but mix them up & it gets ugly...

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Forgive my ignorance, but why would the base deform from a firm crimp? Wouldn't the rest of the bearing surface of the bullet, in moving forward, plus the obturating effect of the pressure in the case, flatten out the crimp before the base passed that point?

I've been told that marking/creasing a jacketed bullet with too much crimp was a bad idea, because that much compression might separate the jacket from the core. I didn't think that that would happen to a plated bullet, where the plating is bonded to the core.

Thanks for enlightening me B) .

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Just one guy's opinion.

Autoloader round " crimping " does not seem to bother them .

Roll crimp , as in revo rounds ( 357 in my case ), will cause the plating to split at the crimp. I cannot solely blame the poor accuracy on this condition alone, but rounds similarly crimped seemed to generally not shoot well at all.

My 45acp likes .469 -.470 just fine, never pulled a bullet to see if it was creased.

Travis F.

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I’ve been following this thread with interest; everyone’s experience is so different than mine. Granted I only tried once but my outcome was dramatically different. West Coast’s 200gr SWC 1.250 OAL and .468 crimp = 2 ½-3” 10 yard group. Not changing a thing on my press EXCEPT the crimp (.470-.471) yielded groups that could completely covered with a nickel.

Of course this was in MY gun with MY brass loaded with MY loader and with ONE lot of bullets. Apparently it was an aberration. It just goes to show that one shouldn’t jump to conclusions. Thanks for bringing this up, I learned something.

Ed

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Having used West Coast bullets in my .45 Edge, I found best accuracy with little to no crimp. This was a tip given to me by a friend who shoots bullseye competition. Problem was: if there is NO crimp how can you avoid the danger of possible bullet setback? I switched to hornady OneShot case lube (thanks Brian!) and a Lee brand "U" or "U"ndersize resizing die. This gave the "coke bottle" or "hourglass" shape to the rounds that Brian talks about in his excellent video. It also prevents setback. Not surprised to hear that others got better accuracy with some crimp; just goes to show you must expirement with your equipment to find what works.

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Problem was: if there is NO crimp how can you avoid the danger of possible bullet setback?

Even though you already answered the question a bit...I want to take this opportunity to point out...

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

The crimp does NOT hold the bullet.

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LOL Flex

Where do people get the idea that crimp does hold the bullet in place?

I can't tell you the amount of times that some new guy comes up to me at the range and is proud to show me his new reloads, and I see a mushroom head sticking out of the case, then I show them one of my rounds and they say you don't crimp at all, and I say watch they shoot just fine don't they? and no set back.

Bob

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Great timing on this thread!! I am just about to switch over to a plated bullet for the first time. Everyone I know who has used plated .45acp bullets has said that there should be little to no crimp. When I mentioned that some people were saying you should use more crimp, they looked at me like I had been snorting lines of gun powder. I will start with no crimp, and take it from there. Thanks for everyone's insight.

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Again, I plead ignorance. I know that the bullet is held by an interference fit between the case wall and the bullet bearing surface, and that in autoloading cartridges that is usually (if done properly) enough to prevent bullet setback as it hits the feed ramp and avoid dangerously high pressures in the case. But doesn't a roll crimp into a cannulured revolver bullet serve a real purpose in keeping the chambered bullets from moving out (set forward?) in recoil, and thereby preventing binding of the cylinder? If so, why isn't there "set forward" in autos? Or does it happen and nobody cares, because it doesn't affect safety/performance? Or do auto mags let cartridges slide fore and aft so that there isn't any movement of the bullet in the case, as opposed to a revolver cylinder which may act more like a kinetic bullet puller in recoil?

I have a headache... :wacko:

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