Bullets with cannelures And Crimping ?
- Thread starter Lodgepole
- Start date
I shot M1 & M1A in competition for years and never crimped w/o issue, so when I started coyote hunting with an AR continued that practice until I dumped a load of powder into the action of my AR. Problem was that I made a practice of extracting the loaded shell and placing it back on top of magazine. No telling how many times the offending round had been chambered before bullet was loosened enough to be a problem. If you load by dropping round in chamber and easing bolt forward gently, then using forward assist to fully chamber/lock bolt, no crimp would be fine. I started crimping since I drop the bolt on loaded magazine to chamber the first round.
ETA: Got by w/o crimp for probably a year or more before it presented a problem.
Regards,
hm
ETA: Got by w/o crimp for probably a year or more before it presented a problem.
Regards,
hm
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Bowhntr6pt
Well-known member
You will find two camps on the subject... those who crimp ammo intended for any semi-auto use and those who do not. I don't crimp any bolt gun intended ammo.
Those who do not will cite years of trouble-free results and some who advocate it will cite reasons as well, such as mentioned above.
Depending on how much you crimp, it is possible to adversely effect accuracy of the load due to bullet jacket deformation but to what significant degree is a topic of great debate.
Safety reasons include preventing bullet set back in the case when running up the feed ramp.
For my blasting loads(FMJ ammo) in .223 I will crimp to make sure I have no issues. On any ammo intended for my auto-loading .308 Win. rifles I will light crimp using the Lee Factory Crimp Die (FCD). Using a magnifying glass, I adjust the crimp die until I just can see evidence of the crimp, this process has served me well for years, provides for a meaningful crimp with minimal effect on bullet jacket. I do this in the .308 gas guns because the recoil on the 16" can be quite sharp.
On my hunting ammo smaller than .308 Win I might crimp, I might not, depending on how the bullets feel when I seat them... if they feel like there's good solid neck tension I usually don't. I just finished up 300 rounds of 6.8 and 300 rounds of 6.5 Grendel, they felt solid/tight on the seating so I did not crimp.
So, for me:
Any Bolt Gun Ammo- no crimp
.223 FMJ Blasting ammo- crimp
.308 Win ammo, FMJ Blasting or Hunting- very light crimp
Other Semi-auto Loads- Depends on neck tension
So as you can see, I'm all over the place when it comes to crimping...
Those who do not will cite years of trouble-free results and some who advocate it will cite reasons as well, such as mentioned above.
Depending on how much you crimp, it is possible to adversely effect accuracy of the load due to bullet jacket deformation but to what significant degree is a topic of great debate.
Safety reasons include preventing bullet set back in the case when running up the feed ramp.
For my blasting loads(FMJ ammo) in .223 I will crimp to make sure I have no issues. On any ammo intended for my auto-loading .308 Win. rifles I will light crimp using the Lee Factory Crimp Die (FCD). Using a magnifying glass, I adjust the crimp die until I just can see evidence of the crimp, this process has served me well for years, provides for a meaningful crimp with minimal effect on bullet jacket. I do this in the .308 gas guns because the recoil on the 16" can be quite sharp.
On my hunting ammo smaller than .308 Win I might crimp, I might not, depending on how the bullets feel when I seat them... if they feel like there's good solid neck tension I usually don't. I just finished up 300 rounds of 6.8 and 300 rounds of 6.5 Grendel, they felt solid/tight on the seating so I did not crimp.
So, for me:
Any Bolt Gun Ammo- no crimp
.223 FMJ Blasting ammo- crimp
.308 Win ammo, FMJ Blasting or Hunting- very light crimp
Other Semi-auto Loads- Depends on neck tension
So as you can see, I'm all over the place when it comes to crimping...
arlaunch
Active member
Lots of good information has already been stated.
I have a Redding T7 press and a Lee factory crimp die that lives in one of the holes. It is a great tool and IMO way on better than the roll crimp design associated with cheap bullet seating dies.
I have chambered/ejected many rounds like HM1996 has over the years. I have actually spent a lot of time measuring them with calipers when i get back home also. No real problems with set back yet. Though i have seen the bullets start to unseat 2-3 thousandths from time to time.
Any round that gets chambered/ejected 2 times turns into a fouler round.
You do not need to crimp! Especially when you do not plan to chamber/re-chamber very often.
If a bullet has a canelure though, it is difficult for me to not crimp it for some reason.
No matter which way you shake it, a crimp done correctly increases reliability.
I have a Redding T7 press and a Lee factory crimp die that lives in one of the holes. It is a great tool and IMO way on better than the roll crimp design associated with cheap bullet seating dies.
I have chambered/ejected many rounds like HM1996 has over the years. I have actually spent a lot of time measuring them with calipers when i get back home also. No real problems with set back yet. Though i have seen the bullets start to unseat 2-3 thousandths from time to time.
Any round that gets chambered/ejected 2 times turns into a fouler round.
You do not need to crimp! Especially when you do not plan to chamber/re-chamber very often.
If a bullet has a canelure though, it is difficult for me to not crimp it for some reason.
No matter which way you shake it, a crimp done correctly increases reliability.
When I develop my 223 loads I let accuracy of the load determine if I crimp or not. When I do crimp I always use a Lee Factory crimp die. It's been my experience, with my AR's, that a light to moderate crimp usually enhances accuracy especially with most bullets 65 grains and lighter. When I settle on a particular powder, bullet, brass and primer combination I always continue testing with OAL and crimp or no-crimp variations.
With bolt gun loads, I usually find the opposite to be true and rarely crimp them.
Edit: I should also add that for cannelure bullets sometimes I seat them to the cannelure, sometimes not, meaning that I just ignore the cannelure and seat them to the most accurate OAL. And crimp or not with no regard to the cannelure ensuring that they fit my magazines.
With bolt gun loads, I usually find the opposite to be true and rarely crimp them.
Edit: I should also add that for cannelure bullets sometimes I seat them to the cannelure, sometimes not, meaning that I just ignore the cannelure and seat them to the most accurate OAL. And crimp or not with no regard to the cannelure ensuring that they fit my magazines.
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reloader326
Member
I once asked a Hornady Engineer if ALL of their factory ammo was crimped. He said yes.
Unless you are hand feeding your rounds, my advice is to always put at least a light crimp on your AR rounds. Maybe a heavier crimp on plinking / blasting rounds.
Unless you are hand feeding your rounds, my advice is to always put at least a light crimp on your AR rounds. Maybe a heavier crimp on plinking / blasting rounds.
Crimping can either be a headache or another tool to get desired accuracy/velocity. In a bolt gun I always start without a crimp. If find a combination and want to do some fine tuning I start playing with crimp. But I never coyote hunt with ammunition that’s not crimped to some degree. Do I believe it’s a necessity in every gun? Certainly not, but it’s one less factor in the field I have to worry about. Consistent neck tension is the only way you can guarantee consistent accuracy. When you don’t crimp you can’t guarantee that neck tension is the same case to case. Now if you turn necks it will to some degree give you consistent neck tension, but you can’t account for the softness from case to case. Some may say annealing can fix that. So all in all it’s all in what you and your rifle are comfortable with. Sure makes food for thought though.