to crimp or not to crimp ?

[dave338]

ive been asked to load some 175mk for a friend , wants a load like swiss p ball, or lapua 185gr

does anyone know if this stuff is crimped?
if you have some, would really appreciate some data on oals
or length to og ,
also recomendations on powder that flows well though a harrels
thinking 2460-blc2-335 ?
any advise / comments welcome
cheers

 

[Grumulkin]

Re: to crimp or not to crimp ?

Can I presume you're loading for a 308 Winchester?

1. You don't need to crimp 308 Winchester loads.

2. The 308 shoots well with various powders. I use IMR 4064 mostly but Varget should work well and I'll likely try IMR 8208 XBR.

3. In determining the best COAL, there are 3 main rules to live by:

A. There needs to be at least a bore diameter of bullet in the case.
B. The cartridges need to feed through magazine.
C. Most bullets shoot best when loaded as near the lands as possible.

 

[dave338]

Re: to crimp or not to crimp ?

thanks for that,
ive been loading my own stuff for a long time ,
but a friend wants a copy of the swiss p or lapua 185,
apart from bullet weight ive no info on these
hence looking to see if they are crimped and some oals ?
looking to load 5000 so want a powder that meters well,
also looking at the lap d46 fmj, lap 185 scenar

 

[samnev]

Re: to crimp or not to crimp ?

I've never had to crimp any of my 308 loads in any bullet weight. Ball powder will usually meter much better than any stick powder. I use IMR 4895 for my 308 load but skip the Dillon powder measure station and use the RCBS Charge Master 1500 for dropping powder then continue on the Dillon 550B. OAL on my loads is 2.80" +/- .005"

 

[gcoulsey]

Re: to crimp or not to crimp ?

The lapua website has load data on it for it's projectiles,
They use viht powder, and as I recall, the accuracy load for the 185 scenar
Is with vvn550.
I don't have the links to hand, but I think it's pretty easy to find on there,
Alternatively go direct to the viht powder website and check out the load info there..

 

[dave338]

Re: to crimp or not to crimp ?

cheers
will stick to the lap data, good web site .
thanks for input.
as soon as i get it loaded will post targets and results

 

[gcoulsey]

Re: to crimp or not to crimp ?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dave338</div><div class="ubbcode-body">cheers
will stick to the lap data, good web site .
thanks for input.
as soon as i get it loaded will post targets and results</div></div>

Please do, I use n550, and have a box of 185 scenars myself that I keep meaning to work up, but havnt gotten around to it yet!

 

[dave338]

Re: to crimp or not to crimp ?

the last lot of 185 scenars i loaded with n550 @ 46.5grs
gave quite good results
5 rds
2588 1st shot cold & clean
2672
2647
2628
2629
[img:left]http://

[/img]

 

[Advokaten]

Re: to crimp or not to crimp ?

To answer the org question,

yes Lapua factory stuff will have a slight crimp, one that is hard to make at home, or at least I think so.

But besides that the rest has been told.

/Chris

 

[dave338]

Re: to crimp or not to crimp ?

thanks sg
why do you think the crimp would be hard to do?

 

[Grumulkin]

Re: to crimp or not to crimp ?

If you wish to crimp, consider the Lee Factory Crimp Die. While there are other ways to crimp, in my opinion, that die is the best for that purpose.

 

[gcoulsey]

Re: to crimp or not to crimp ?

That last load looks promising, with only 1 fouling shot on a clean barrel,
Subsequent groups might see the velocity settling down a bit to a lower ES.

As already mentioned, I wouldn't worry about the crimp unless you think there's a specific need for it? Tube magazine, or expecting lots of rough handling in the field?
You say your making up 5000 for your friend?
Are you shipping those rounds 'abroad' by any chance?

 

[dave338]

Re: to crimp or not to crimp ?

the 185gr does look good , used it again at the weekend,
still not sure if i should crimp the ones on order,
the client? is looking for a replacment for current swissp/lapua which he has been using,irregular supply, and uses a lot
guess i will just load ten and crimp , see what happens,
dont really want to use the vit n550 because it does not meter that well
lap brass-lap heads-cci br2 primers- n550 = expensive

this target is from the weekend
guess how many rounds, distance is 200y
guess right and i will give you a box [img:left]http://

[/img]

 

[targaflorio]

Re: to crimp or not to crimp ?

10 shots. Nicely done!

 

[dave338]

Re: to crimp or not to crimp ?

close , but no prize!

 

[Unsichtbar]

Re: to crimp or not to crimp ?

A couple of top end shooters ( QC engineers statistical type guys )that have access to CED pressure trace equipment swear by Lee Crimp die to just touch the case to add tension. Thats the key just a touch less than .001 compression not really a crimp. I saw there Pressure traces and the FPS ES and barrel times came together after applying slight preasure. I have been doing it since and shoot mainly long range were vertical spread would show.

Set up, run loaded round up, turn Lee die to just touch case then 1/8 to 1/4 turn, scribe witness mark to be able to duplicate.

 

[dave338]

Re: to crimp or not to crimp ?

seems lee gets top marks for the crimp, had a few recomendations now for their die.
only one way to find out !
should be picking one up on saturday,

 

[gcoulsey]

Re: to crimp or not to crimp ?

Ten shots plus a cold bore, making eleven?
Either way, VERY nice group!!
Was that freehand off horseback too?

 

[dave338]

Re: to crimp or not to crimp ?

1ts actually 12, from a bench using bipod,loading at the point
the top one is the 1st shot
no wind and the stars alined!!!!

blind folded on horseback sounds a lot cooler

drop me a pm next time you get to bisley, quite often at 100-200y

 

[Unsichtbar]

Re: to crimp or not to crimp ?

You might find this fellows crimp vs no crimp teste of interest.

http://www.accuratereloading.com/crimping.html

Real interested in how this works for you, might take a little experiment with how much is enough, for me less is better.

 

[dave338]

Re: to crimp or not to crimp ?

unsichtbar
thanks for the link, very interesting results not what i expected to see, should hopefully be testing next week

 

[Greg Langelius *]

Re: to crimp or not to crimp ?

Change a factor, and you change the load. Without doing at least some rudimentary load redevelopment in conjunction with the crimp, ideal load/barrel compatibility may become somewhat less certain. The test does not appear to take this possibility into consideration.

Greg

 

[dave338]

Re: to crimp or not to crimp ?

ok loaded six rounds of what i normally shoot, crimped three only lightly on the lee factory crimp
shot all six, group measured .35" center to center at 100y
no sign the crimp had any effect.
did test the crimp pressure buy loading and chambering 3 times in an ar rifle, letting the bolt slam forward, factory ammo the oal grew by .30-.40" must of had no crimp, the three i crimped did not move.
so as far as i can see a light crimp will not harm accuracy,
the bullets i used were sierra mk

 

[Unsichtbar]

Re: to crimp or not to crimp ?

Thanks for the up date, of course were you will see improvement is at extended ranges, vertical spread at 600 yds & 1000 yds. If you chrongraph some rounds ( at least 10 or more of each if possible ) you might see some tighting of ES, the CED pressure trace really showed improvement but not that many of us have access to one.

 

[awp762]

Re: to crimp or not to crimp ?

Here are my measurements on the factory lapua 185gr & 170gr HPS:

Length to ogive using sinclair green body & 30 cal insert: 2.129"
factory OD of loaded neck: .3384"

Lapua 170 gr HPS: length to ogive 2.108"
Neck OD .3388"

 

[dave338]

Re: to crimp or not to crimp ?

should be out at 600y next week so will do the same again,
next thing is to get a metplat trimmer! just had some bergers that had really raggy points, .
will trim more for max oal for mag feeding than accuracy,
cant complain about that , won the match on sunday with them.

 

[dave338]

Re: to crimp or not to crimp ?

should be out at 600y next week so will do the same again,
next thing is to get a metplat trimmer! just had some bergers that had really raggy points, .
will trim more for max oal for mag feeding than accuracy,
cant complain about that , won the match on sunday with them.

cheers for those measurements,