how far out or in

CarlW

Well-Known Member
crimping is onley good in semiotomatic guns has no real world value in a bolt gun try not crimping longer bras life if your dies are set up right there is no nead to crimp
Two reasons that I crimp:

  1. I get tighter groups in all of my rifles (presumably due to better consistency of neck tension);
  2. In heavy-recoiling dangerous game rifles, the loaded ammo gets pretty beaten up in the magazine and I want to avoid compressing the bullet into the case and thus increasing pressure (particularly in a hot country).
Kind regards,

Carl
 

paul o'

Well-Known Member
I load Saami for the .243 but the 280 ack likes less of a jump and as I load out of a mag for hunting the mag has to be the my max aol I can use, unless I hand feed each round :tiphat:
 

Sonicdmb73

Well-Known Member
Two reasons that I crimp:

  1. I get tighter groups in all of my rifles (presumably due to better consistency of neck tension);
  2. In heavy-recoiling dangerous game rifles, the loaded ammo gets pretty beaten up in the magazine and I want to avoid compressing the bullet into the case and thus increasing pressure (particularly in a hot country).
Kind regards,

Carl
I will add to that. My ES is single figures and groups better for crimping. It is only a light crimp but it does make a difference.
 

LeftHandGuy

Well-Known Member
Surely a cannelure is simply the manufacturers method of securing the jacket to the core of the bullet? It doesn't mean you have to crimp on it or use it for anything, its just part of the bullet construction...I think!
Are you confusing the Hornady "Interlock Ring" with the cannelure? I ask because I thought they were the same at first, until I looked at the diagram more closely: https://www.hornady.com/bullets/interlock#!/ obviously that's just one manufacturer but they claim it both secures the jacket and is a location for a good crimp.

crimping is onley good in semiotomatic guns has no real world value in a bolt gun try not crimping longer bras life if your dies are set up right there is no nead to crimp
The only semi-auto I have is a pistol - and crimping is absolutely 100% necessary for that particular gun, the bloody thing will not chamber at all if I don't (Yugslaviam M57 Tok' style in 7.62x25). For the others (bolt and lever guns) it seems to make a mild, but perceptible increase in accuracy - could even be a placebo.

In 35 Remington I shoot the 220 grain flat point over a reasonably stout charge, and the other rifle calibre I'm loading at the moment is 375 H&H which, even in lighter loadings generates a pretty decent amount of recoil. Consistency is key; once I seat a bullet I don't want the bloody thing to move until it's in the chamber and I press the trigger.

I concede that this may not trouble you in some of the more conventional stalking calibres - as I say, I just allow myself to be signposted by the maker of the bullet as to where to apply a crimp, in the confident knowledge that they, as people who know more about bullets than I do would crimp it there if faced with the choice of doing so or not. And that this approach has inoculated me from the temptation to "chase the lands"...
 

Blobby159

Well-Known Member
Absolute rubbish.
There can be and often is significant advantage in crimping whether using a Lee FC die or roll crimping into a cannelure.
There is a problem with crimping rifle bullets when there is no real need to - as in relatively mild recoiling rifles - and contrary to some respondents here it will not necessarily improve consistency of velocities IF the cases HAVE NOT all been TRIMMED to the same consistent length each and every loading cycle!

In the absence of very persistent trimming of case lengths the crimping will apply a varying degree of "stay-in-there-ness" as slightly more or less case neck brass will then be involved (bent into the bullet circumference) which must be overcome before the bullet/projectile is released. It is generally suggested in reloading for accuracy that the complete absence of a crimp is the way to go because of that!

As has been discussed earlier, with hard recoiling rifles fed by a magazine wherein the rounds do get significant jolts with previous rounds being fired, sufficient crimping is a definite requirement, preventing rounds in the magazine being altered in length (potentially) by the heavy recoiling of the rifle either bashing the bullet further into the case or alternatively, the recoil jerk acting on the rounds as if they were in a kinetic bullet pulling mechanism,.. either way potentially altering seating depth of the bullets....


B.T.W. "Heads" with reference to completed cartridges should really ONLY refer to the 'Case Head' i.e. that bottom end of the case which is designed with the strength to contain fired pressure of the round, to hold the primer and which has a rim &/or groove of some sort to enable extraction of the empty case from the chamber after the cartridge has been fired.
The bit that gets fired from the rifle barrel is the 'bullet' or the 'projectile'. ... Thank you.


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Alantoo

Well-Known Member
No answers yet...could some of the experienced loaders share their findings and put some numbers to the group size improvement made by adjusting the seating depth?

Alan


Those of you that have found it advantageous and advocate longer than the bullet manufacturer's recommended COAL...having arrived at your optimum powder load how many rounds do you fire to assess the advantage of a particular COAL?

How precisely do all the subsequent groups you fire at your chosen COAL setting reproduce your initial experiment?

How consistent does your shooting need to be in order to be able to assess the COAL variable? What is you average five-shot-group size STDEV?

I have only been reloading for a few years and only for one hunting rifle, but after reading many posts on here about the advantage I was surprised at how little difference extending the COAL made to my groups...it was much more likely to be varied by ambient temperature, that days aches and pains or the meal I eat before shooting!

Can you quantify/specify the advantageous effects you found with some statistics? ie number of rounds fired at various lengths and the resulting group sizes and then the constancy of subsequent groups?

Alan
edited, italics added since first posted
It was because of the general statements made earlier in the thread that I was wondering if those of you with experience could share a little more detail about the advantages you found by tweaking the COAL. So that there is something for the rest of us to gauge our results and calculate with.

Alan
The reason I have been asking for some group size figures demonstrating the difference, is that my groups have a large variation on a day to day basis. So my average of 0.602" over 9no. 5-shot groups has a STDEV of 0.228 and a best and worst of 0.308" to 0.906" and I wondered how a nuance like varying the jump to the lands was identified in the groups by those that had found it advantageous.

Alan
 
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Muir

Well-Known Member
Absolute rubbish.
There can be and often is significant advantage in crimping whether using a Lee FC die or roll crimping into a cannelure.
This. I crimp everything. If Lee doesn't make a FCD for what I'm shooting I have them make one. Anyone who says there is no value to it has never done it. Smaller ES/SD. Zero reduction in brass life.~Muir
 

Sonicdmb73

Well-Known Member
No answers yet...could some of the experienced loaders share their findings and put some numbers to the group size improvement made by adjusting the seating depth?

Alan
Unfortunately I don’t have figures to give you. I know it improves my groups. I also know it has made a difference to ES. But I don’t have a correlated record of results. Because once I have found what works I tend to stick with it.
 

Alantoo

Well-Known Member
Unfortunately I don’t have figures to give you. I know it improves my groups. I also know it has made a difference to ES. But I don’t have a correlated record of results. Because once I have found what works I tend to stick with it.
Thanks for the response...I know what you mean about sticking to what has worked...it is what I have done...I did try various seating depths but they did not make a significant enough difference for me to be certain it was anything other than just standard group variations.

Having read this excellent article Shooting - Group diagnosis I have relied on quantity of results to make any assessment...and sadly for my ego that included all the bad groups...so I base my confidence in the load on its worst performance at the range...knowing it will likely be better.

I have used manufacturer's COAL as the starting point, and taken advice from what seemed to make sense to me from t'internet...some bloke called @Muir has caused me to Lee Factory Crimp everything in sight for instance.

I have read that some advocate starting off basic load development at a few thou off the lands or the maximum possible COAL, and then having found the best powder load, reduce the COAL to find the best groups...the idea being that way round the risk of over pressure through approaching too close to the rifling is then being reduced.

However...What I am not sure about what you mean, is that you "know it improves" your groups but you can't say by how much? So how do you "know"?

Alan
 

LeftHandGuy

Well-Known Member
However...What I am not sure about what you mean, is that you "know it improves" your groups but you can't say by how much? So how do you "know"?

Alan
In my case, I don't really bother to measure until I feel I am approaching an acceptable group size (albeit my only real variable is charge weight) - so could be similar?
 

Sonicdmb73

Well-Known Member
Thanks for the response...I know what you mean about sticking to what has worked...it is what I have done...I did try various seating depths but they did not make a significant enough difference for me to be certain it was anything other than just standard group variations.

Having read this excellent article Shooting - Group diagnosis I have relied on quantity of results to make any assessment...and sadly for my ego that included all the bad groups...so I base my confidence in the load on its worst performance at the range...knowing it will likely be better.

I have used manufacturer's COAL as the starting point, and taken advice from what seemed to make sense to me from t'internet...some bloke called @Muir has caused me to Lee Factory Crimp everything in sight for instance.

I have read that some advocate starting off basic load development at a few thou off the lands or the maximum possible COAL, and then having found the best powder load, reduce the COAL to find the best groups...the idea being that way round the risk of over pressure through approaching too close to the rifling is then being reduced.

However...What I am not sure about what you mean, is that you "know it improves" your groups but you can't say by how much? So how do you "know"?

Alan
Quite simple I tested it. Groups improved. Chronograph results showed improved ES.
I don’t have the load test data, so can’t say if it halved the group or what. Would you rather I made something up?
 

Blobby159

Well-Known Member
I am similar in this respect at least to 'LeftHandGuy' and 'Sonicdmb73' in that I just shoot and make mental notes of the changes to group size - good or bad - and keep experimenting initially with depth of bullet seating and once I get the kind of improvements I was anticipating (AT LEAST below 1 M.O.A. group size or less) by first doing that, I then tinker with propellant charge weight to see if doing THAT might offer an improved group size as well as hopefully an increase in velocity.

As I have NEVER bought bullets with cannulas imprinted into their shanks I have never played with loading bullets to these said immoveable depths, though it is entirely possible that my final C.O.A.L.s might be of similar even identical lengths to those if I had used the cannula versions of my projectiles.?

The final seating and bullet depth control is obviously a more complex "science" than either side of this "To Crimp or Not to Crimp" argument would suggest, in that BOTH methods obviously give really excellent group size results. I find this intriguing in that two, on the face of it CONFLICTING methodologies can and do actually give quality & repeatable results, .... and If I had the time, the money (and perhaps the sponsorship support?) I should be interested in investing some of my time and deep thinking into a bit of real solid experimentation regarding this interesting question, but as it is I will stick to my proven methodologies as they give me repeatable quality results that I am loathed to trash..

In the FINAL Analysis the message here I think is "if it works and works well, don't fret and just keep doing it!!

ATB ..... and safe shooting


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Ozalid

Well-Known Member
You know, I'm beginning to think this is all smoke and mirrors, just to put this into perspective, 10 thou is approximately .25 of a millimetre and try as I might, I cannot envisage that changing by even 40 thou/1mm, is going to make the slightest difference to how the bullet engages the lands.
To crimp or not to crimp, that is the question, after I have loaded my cases they grip the bullet as tight as a Scotsman gripping a quid, so why crimp, it just doesn't make sense to me.
So my final thought is this, if you are a bench shooter who is anally trying to put every shot through the same hole, fine, you can happily bugger around with the minutiae of all the various elements of reloading, the combinations are almost endless but you will probably die a bitter and frustrated man, or, if you are a hunter, just having the confidence that you can hit a 4" circle consistently at up to 250 yds (my personal limit), then why worry? You are fine and life is good.
 

Alantoo

Well-Known Member
Quite simple I tested it. Groups improved. Chronograph results showed improved ES.
I don’t have the load test data, so can’t say if it halved the group or what. Would you rather I made something up?
No no no...quite the opposite...it is because I am trying cut through the hearsay to some actual figures I am persisting with the questions...and I am not trying to catch you out or wind you up...quite the reverse...I am very grateful that you are responding.

I am trying to get an idea of what I should be looking for in my group improvement which can be identified as resulting from seating depth variation. Because my groups have such a wide variation is it pointless my considering seating depth until my shooting has improved and I maybe explore a heavier barrelled rifle for instance?

How consistent were the groups relatively before and after having settled on the given seating depth?

Alan
 

Blobby159

Well-Known Member
'Ozalid'...

It can also be a fine thing to do all you can to get the best result out of what it is one is involved in, whether or not others view your erm... let's say 'extended' hobby as an anal waste of time!?... It makes me and others like me happy to be 'anal' and it harms no-one. Neither am I forcing MY point of view onto anyone that asks me and or reads what I write down as my own considered P.O.V. in places like this fine discussion area. I wholeheartedly agree that downing a deer at even fairly extended ranges does NOT require the type of benchrest accuracy some of us apply to this task, but I bet others in my 'anal brotherhood' agree, knowing precisely where a well aimed bullet will land is a great bolsterer & sustainer of one's Confidence. This is probably as important if not MORE SO than real life accuracy - given the actual size of our given target(s) is actually quite large and forgiving of minor deviations from the ideal...

Regards,
Blobby159


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Orion

Well-Known Member
....... so why crimp, it just doesn't make sense to me.
For another initial level of consistency that can be applied when developing loads and before faffing around with bullet seating ‘off the lands’?
 

Sonicdmb73

Well-Known Member
No no no...quite the opposite...it is because I am trying cut through the hearsay to some actual figures I am persisting with the questions...and I am not trying to catch you out or wind you up...quite the reverse...I am very grateful that you are responding.

I am trying to get an idea of what I should be looking for in my group improvement which can be identified as resulting from seating depth variation. Because my groups have such a wide variation is it pointless my considering seating depth until my shooting has improved and I maybe explore a heavier barrelled rifle for instance?

How consistent were the groups relatively before and after having settled on the given seating depth?

Alan
You need to be consistent with your shooting. Otherwise you don’t know if you’re having a good or bad day vs the change made to the load.
A heavier barrel helps stop heat affecting your group. My CZ550 in 243 opens up if I fire more than three rounds one after the other. My heavy barrel 222 is not affected the same way.

In an earlier post you said your average group size was 0.816” over 32 groups. But what are the best and worst of them? Until you can get the difference between those as small as possible. You will just be second guessing yourself.
 

Sonicdmb73

Well-Known Member
You know, I'm beginning to think this is all smoke and mirrors, just to put this into perspective, 10 thou is approximately .25 of a millimetre and try as I might, I cannot envisage that changing by even 40 thou/1mm, is going to make the slightest difference to how the bullet engages the lands.
To crimp or not to crimp, that is the question, after I have loaded my cases they grip the bullet as tight as a Scotsman gripping a quid, so why crimp, it just doesn't make sense to me.
So my final thought is this, if you are a bench shooter who is anally trying to put every shot through the same hole, fine, you can happily bugger around with the minutiae of all the various elements of reloading, the combinations are almost endless but you will probably die a bitter and frustrated man, or, if you are a hunter, just having the confidence that you can hit a 4" circle consistently at up to 250 yds (my personal limit), then why worry? You are fine and life is good.
If you’re happy hitting a 4” inch circle at 250 then all’s good.
But that’s no good for me, it’s a missed fox or crow. Or maybe a deer not hit as cleanly as it could be. I want half MOA from prone under the best conditions. Because you can guarantee that you won’t get best conditions for accuracy whilst hunting. Better to reduce errors where you can.
 

Alantoo

Well-Known Member
You need to be consistent with your shooting. Otherwise you don’t know if you’re having a good or bad day vs the change made to the load.
A heavier barrel helps stop heat affecting your group. My CZ550 in 243 opens up if I fire more than three rounds one after the other. My heavy barrel 222 is not affected the same way.

In an earlier post you said your average group size was 0.816” over 32 groups. But what are the best and worst of them? Until you can get the difference between those as small as possible. You will just be second guessing yourself.
Best 0.5" and worst 1.209" STDEV of 0.202 those were the factory HPS. But your point is exactly why I was asking the experienced reloaders for some numbers to compare with. How close should the groups be and over how many groups do you average to make an assessment, before seating depth effect can be observed and identified?
 

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