I've never bothered to crimp any of my rifle loads, mainly because most of them are fairly mild shooters (.243, .22-250, .308). I noticed some flattening of the exposed lead tips on the Nosler Partitions I'm loading for the .300 Win Mag and suspect there is some set-back in unfired rounds removed from the magazine, but I haven't had the time to go through them yet. Accuracy doesn't seem to suffer, I'm getting .75" groups or better (@100 yards).

I've been thinking about ordering the Lee FCD, just to try it. Should I back off my powder charge and work back up, looking for signs of excessive pressure? The load I'm using is 79.4 grains of H1000. Nosler lists 81.0 as a MAX, and I've loaded slightly above this (81.4) without seeing any excess pressure signs.

I'm sure this has been discussed somewhere in the forums before, but a search turned up very few results.

Id measure your unfired rounds out of the magazine and compare with your oal measurements of a new round if you reload or factory round if you dont.
If you are seating the projectile deeper with recoil in the magazine, then you either need to increase your neck tension or crimp the necks.
As with any changes back off the charge and work your way back up in the usual ladder loading way and check for pressure signs and accuracy.
I dont think crimping will make a great deal of difference, but the win mag is a powerful round so be safe.
Let us know what happens.

I'm with dhc, use a comparator to see if the "fresh" loads are different from the ones that have spent time in the magazine. I'm looking forward to your findings! Regardless, a proper crimp sure can't hurt anything.

On the recommendation of some of the fine folks here I bought a Lee FCD for my semi-auto .223/5.56 loads. I haven't done any measurements to see if it had much effect but it makes me feel better!

HJ...Pete and Punkin have pretty much covered the “che is and balances” mate, but personally, I crimp all my centrefire rounds. As Punkin said, it makes him feel better...but there is also knowing that every round has sufficient crimp to hold the projectile steady and with a uniform grip from round to round. Consistency has to count for something, in which case I highly recommend the LEE FCD. Nothing to loose, everything to gain mate.

If you don’t already do it, I strongly recommend trimming to length, especially the .243 and 22.250 (both of which are notorious for “growing”), every third loading...and checking for signs of head separation. This will add more consistency to your loads. It’s not a biggie or war winner, but you can also anneal your cases every third loading to increase case life.

Crimp? I don't leave home without it!

Never use the integrated crimp feature in the bullet seating die (Elvis, taught me that tip). Good you got the dedicated Lee FCD. No need to be in the cannelure. In my .270 Win, crimping did not increase neck tension but did reduce variation in tension by 50% - measured with a force gauge pulling bullets. I use a medium crimp, e.g., 0.003" indent in the brass (collet pedals not touching).

It wouldn't be wrong to reduce your powder charge but you are already 1.5 grains below max. I would crimp and go.

I made myself curious, so I dug through the mess on my loading bench.

It doesn't appear that bullet set-back is an issue, which kinda surprised me. "New" rounds measure 2.730" with a Hornady comparator. I measured 8 rounds that had been along for the ride at least once and the shortest I found was 2.727. Other than deformed tips, they don't appear to have changed much.

I'm still probably gonna order the FCD, just 'cause. Midway has them for around $14/each, so getting one for the .223, .22-250, .243, .270, .308, and .300 Win Mag won't break the bank.

General rifle season ended here last weekend, so unless I get a chance to get out for the elk shoulder season, I'm done hunting big game for now. Back to the range and play...

$84, should get free shipping!

my old .270winchester is a real tart for deforming rounds in the magazine...back in bad old days when shooting wallabies with her the bottom round in mag could have up to 15 rounds fired above it and the lead tips got mashed....I got into habbit of trimming it off which worked fine and sure didnt affect accuracy or terminal preformance,also got in habit of putting 2 rounds of ballistic tips in bottom of mag and others above.....now days I dont even bother,most times she only fires a single round and deer dies so its no biggie.
never noticed projectiles getting shunted back,but have seen ribs added to inside of mag box to prevent rounds going forwards.

slimjim wrote:

$84, should get free shipping!

Larry must like you more than me. I couldn't find any offers for free shipping. FCD dies should be here this week

I load A LOT of 7.62x51 for use in an L1A1 semi auto & use a Lee FCD all the time after measuring a couple of rounds out of a mostly used magazine & finding the bullet set back 0.040".
As slimjim says; using the cannelure or crimping a non cannelure bullet doesn't matter, so long as you don't go mad on the crimp.

I seem to be the odd man out here. I only shoot the 7,62x39 and the 5,56/223 in semi-auto guns. I don't crimp for either rifle nor do I see any need to. I have not had any bullet set-back due to recoil and I get acceptable accuracy from both my SKS and my AR platforms. The only cartridge I do crimp is my 357 rounds because the load data requires a heavy crimp with H110 powder.
I have tried crimping my 3006 in the past but found it introduced larger groups that I attributed to inconsistencies in the bullet pull. I have no way to measure bullet pull in any accurate way but the groups almost doubled in size with crimping, from 1/2" groups to just over one inch. My SKS shoots 4 inch groups with crimped rounds and only 2.75 to 3 inch groups without the crimp.
This just shows that some guns do not have increased accuracy with crimped ammo. Each gun is its own combination of characteristics and while some things seem to aid group size across platforms others may not behave the same way in all guns.
I firmly believe you should do what works for your reloads in your guns.

Paul, I read between the lines that you never anneal your cases?

If you develop a load without a crimp then add a crimp, you may have to retune your load.

The only rifle cartridge that I crimp (using a FCD) is .30-30.

I started crimping semi-auto loads when I realized that the bullet could be pushed back, when it hits the feed ramp or front of magazine, or slide forward, when the case stops in the chamber (think inertial bullet puller). As I said, it makes me feel better about the loads.