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Thread: Clambering effect on cartridge and crimping

  1. #1
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    Clambering effect on cartridge and crimping

    Have searched crimp but yields too large, so please bear with me...

    Have been reloading no crimp for AR and satisfied, until:

    Was gifted a bunch of unidentified component 62 and 55 grain fmj bullets. Weight sorted (1.2 grains extreme variation) and separated bullets with lead running up out of the bases. Weighed powder for ladder testing. New, unfired lc brass. Got 3min groups from a 2 min gun. Yeah, not match bullets or gun, but:

    Much, much less effort to seat than other experiences led me to redo and expand on a test once
    Suggested to me:

    Measure headspace, chamber round, remeasure headspace. Paralled previous experience in that there was 2 thou shoulder setback from chambering. What I added was seating depth measurement pre and post chambering. Limited time so only 5 rounds checked, but had seating depth change a thou or 2 BOTH directions.

    Doubt crimping will make big dif in accuracy, but considering cause of ocd. Since I trim gauged from shoulder (typically less than 2 thou hdsp variance) would Lee collet or what be best for consistent crimp?

    Know crimping won't be magic, but I hate having or introducing variation. Chosen loads not hot, so I doubt setback induced pressure spikes, but...

    Thanks in advance....

  2. #2
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    I crimp all my AR ammo now after about a decade or not being a crimper. I noticed that setback was an issue with various bullets. I did see better accuracy after I started using the Lee Factory Crimp Die on my 77gr handloads to the tune of about .2 MOA on average across multiple rifles.

    My process now is FL size with a Redding Type-S without an expanded ball, Sinclair mandrel die for expansion, then seat with a Forster BR seating die followed up with the Lee. This has proven to provide excellent results for me and Iím sure it will for you.


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  3. #3
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    Quote Originally Posted by triggerjerk View Post
    Doubt crimping will make big dif in accuracy,
    You might be surprised. I did a non-crimp test, and my groups grew significantly WITHOUT the lee factory crimp. Exact same batch of 77 gr OTMs shot 3/4 MOA with crimp and double that size without.

    would Lee collet or what be best for consistent crimp?
    Lee works outstanding for me. But my process and other dies/prep could be different.
    "You people have too much time on your hands." - scottryan

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    Quote Originally Posted by markm View Post
    You might be surprised. I did a non-crimp test, and my groups grew significantly WITHOUT the lee factory crimp. Exact same batch of 77 gr OTMs shot 3/4 MOA with crimp and double that size without.



    Lee works outstanding for me. But my process and other dies/prep could be different.
    Mine went from just under MOA to 3/4 MOA with the same complements otherwise just from adding the LEE FCD.


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    Quote Originally Posted by PracticalRifleman View Post
    Mine went from just under MOA to 3/4 MOA with the same complements otherwise just from adding the LEE FCD.
    That's good. Your starting ammo must have been better than mine.

    My theory is that since I don't anneal on .223, the neck tension is less consistent. The LEE FCD mitigates that.
    "You people have too much time on your hands." - scottryan

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    Haven't noticed case oal variation increase since going to trimmer indexing off of shoulder (attempt at more consistent neck length therefore tension?), but still call it a couple or 3 thou case oal variance. Ideas on how much this will/will not affect Lee crimping tension?

    I am guilty of still using expander ball, but do not use shell holder retaining clip on press ram, ball is polished, stem left loose, gently observe/feel/work ram for alignment (case will definitely drop free and crooked as expander ball catches it), and GENTLY withdraw expander (sometimes wonder if folks are working ram like they are stamping license plates...). Don't have measuring tools, but when spinning or rolling rounds, I rarely have a straight case with neck run out. Usually, any crooked cases are bananna shaped (wall thickness variation?) but still have little or no observed neck/bullet runout on the crooked case. Have noticed evenness of case lube application affects case body run out.....

    Note all this worry is because 30 years ago, I never got crimping for 30/30 even close to functional....

    Anyway, have either of you noticed crimping or not to affect powder amount for best accuracy in a given rifle for a given bullet/powder combination?

    Have hundreds of sub minute rounds loaded for another AR, hundreds of these 62s loaded for this rifle, and hundreds of 55s yet to be loaded for another rifle. Seriously contemplating recommended crimping. Guess I could just crimp and test a few of my established loads before crimping them all! Wonder if components will ever become available to totally rework new loads with crimp....

    Best to you and yours in these difficult times and thanks for your time.
    Last edited by triggerjerk; 08-01-20 at 14:17. Reason: I'm goofy

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    Sorry. Last post should have simply been, "Any tips/tricks to offer for one planning to try using the Lee Factory Crimp Die? Note single stage press. Thanks"
    Last edited by triggerjerk; 08-01-20 at 14:38. Reason: Still goofy

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    Quote Originally Posted by triggerjerk View Post
    Sorry. Last post should have simply been, "Any tips/tricks to offer for one planning to try using the Lee Factory Crimp Die? Note single stage press. Thanks"
    I've had good luck with setting the die to where I just get a barely visible crimp mark on the neck.
    "You people have too much time on your hands." - scottryan

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    My load didnít change with crimping. No powder change.

    Like mark, I just put enough crimp on the round to where it can be seen.

    What I noticed on the AR, if I load a round into the chamber, then extract it, there was COAL variation; rounds setting back. That is where I believe my accuracy improved.


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  10. #10
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    At markm, PB and a few others recommendations on here a while back, I tested crimping on my 69gr and 77gr loads. I did a light crimp and it made a noticeable different in accuracy for me. I never got around messing with testing the difference on 55gr but Iím sure it would be the same. I use the FCD also.

    Cheers.

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