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VarmLR

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Posts posted by VarmLR

  1. 1 hour ago, KABOOM said:

    My thoughts are some barrels simply require some fouling to maintain zero, others do not. As for shooter warm up the 2 min prep time we had in the USMC was sufficient to adjust the body and establish the natural point of aim. Having shot NRA junior small bore in my youth I soon learned a clean bore required several sighters to re establish zero. Breath and trigger control are always important and dry fire practice is a very good tool. Calling and plotting shots will teach volumes recording sighting changes and conditions as well. Will heat change the poi?, possibly I think only if the assembly isn't square (thread mating) I haven't seen changes in impact while hot or at least enough to matter. As other have said consistency in cheek weld is important, follow through after the shot and not disturbing your shooting position between shots for any reason. Best wishes for good shooting.

    Agreed.

    Someone relatively new to reloading once asked me what the best way to tighten his groups up.  I responded that dry firing to get consistency of trigger break without gripping the stock or pistol grip tightly, cheek weld consistency and breathing control would half his groups.  He didn't believe me.  His 1.3inch 5 shot groups weren't too shabby for the load he had.  Next meeting, after he'd practised dry firing at home, his group sizes more than halved.  Once I have a 5 shot group of about half an inch from load development, it doesn't take much to tighten those into the 0.3's using disciplined technique.  We all fall foul of slip-ups and none of us I'm sure concentrate 100% on technique 100% of the time.

  2. 3 hours ago, SchmidtP3 said:

    If the warming of the chamber and barrel was a factor, would a string of shots therefore not all result in different POI's? Until you reach a critical temperature and it stabilises?

    It can do just that with a slim barrel profile, but tbh I don't consider that a single round would, or could, warm the barrel or chak,ber enough to make such a difference in POI from cold.  One of my rifles (heavy barrel) has the same POI cold or not....it doesn't seem, to matter but my other two shoot left and slightly low first shot.  The left may well be me not getting correct cheek weld but as this tends to be consistent, it's more likely connected with fouling effects on subsequent firings.

  3. 4 hours ago, Popsbengo said:

    Obturation not obliteration - that's what double loads do 😳

     

    Yes, typo!  Actually it wasn't so much a typo as the settings on my machine changing the damned word that I originally typed!  I have since changed the settings (autofill is infuriating).

  4. Using Wipeout tactical patch out or similar eliminates the need for any oil in the bore as it conditions and protects the barrel.  You can also use sheath cleaner which is a corrosion inhibitor following cleaning followed by a dry patch or M-Pro 7 followed by a dry patch.  I never oil the barrels these days as applying it, dry patch or no, invariably results in residue seeping into the chamber and although I used to dry patch, any oil residues to some extent affect obturation allowing the cartridge to slam back into the bolt (I noticed this especially with my .308).  Cold bore shots imho have a different POI due to powder or copper residues affecting barrel pressures on subsequent shots.  That and perhaps a warming barrel/chamber.  I can't see any other reason why a cold bore shot would differ (but they do!).  

  5. AFAIK you can use a CTR in a TAC A1 Chassis which sort of suggests your stock might be reverse compatible with a TAC action and mag.  TAC A1 is (black) blued.  I don't know why you would want to ditch the TAC A1 chassis though if it's purely for range work as it's one of the finest factory aluminium chassis stocks on any factory rifle.  These things are tack drivers.  Mine has shot tiny 100yd groups, into the 0.1's.  The Bifrost is a superb stock though and has other advantages such as lighter weight and better ergo imho.  I have another Tikka in a GRS laminate and it's the most comfortable shooting rifle prone that I have owned.  It's an expensive route to go though as TAC A1's are over priced here.  I think that some places State side were advertising Tac A1's for $1400 and that they came with 3 mags compared here with £1700 for a rifle with one mag!

  6. Up to 400yds vermin control I used to like a nice lightweight scope so used a Leupold VX3 4.5-14 x 40.  Mine had the BDC ret which was pretty good if not bob-on, you could rely on it to be close enough providing you did a BD test and matched the mag to your bullet drop or as near as it got.  I only replaced that when I started shooting further out at paper and sat a Nightforce NSX on it.  Sightron are ok but I once compared one with my own Bushnell DMR to see what all the fuss was about and was left very underwhelmed by the optics.  It was ok if you just used the centre picture to punch paper but what target shooters like wont necessarily suit vermin shooters.  I prefer something with lens coatings making browns stand out with greater contrast than a target scope typically uses.  The VX3 uses such lens coatings as does the Nighforce I have.  The DMR betters both the Leupold and sightrons for the glass imho but is quite heavy.  A good used vortex viper Gen 2 4-16 x 50 would be a good choice or if feeling flush a S&B PMII 4-16 x 50.

  7. 17 hours ago, martin_b said:

    I tried to take my M55 .223 out to 600 yeards today at Bisley. According to Strelok my 55g bullet should still have been supersonic (1375 f/s) but I tried 3 times and couldnt get any shots to register on the electronic boards. Strelok was bang on with its  vert calc with the .223 @ 300yards and there was very little wind this morning, I did wonder if the scope had moved so checked the rilfe  back at the Zero range but it was fine. Was i just unluckly or getting to the point where the bullet could have started tumbling?

     

    were you using G1 or G7 form factors in Strelock?  Sounds like a G1 BC which won't be accurate over 3 to 400yds.  It's the wrong form factor for the bullet.  Swap to a G7 and tune the velocity to measured velocity to re-set actual BC and it should sort things out.

  8. I think it may be difficult for many to get an ELR rig on ticket until there's a venue for shooting them.  I know that some clubs allow HE up to and including 50 Cal, but having let my membership go on one of them due to disappointments in the lottery which was "will we get a shoot this month?" which went on for much of the year last year, and issues with it's manangement, it was a let down.  If a dedicated ELR "club" were set up with a purpose made venue, reasonably accessible,  I'd put in for a variation and have a rig built up, possibly in 375, 408 or 416.  It's a bit chicken and egg at the minute though. 

  9. 9 hours ago, KABOOM said:

    Glad things are working out! My worst error was using data with one bullet and I used another with about twice the bearing surface.

    At 32 degrees F it was ok the velocity was high enough to make me smile and I should have realized things were amiss. Sadly I didn't until summer. Stiff bolt lift, very flat primers made me look at things closer. After that shoot I disposed of all that brass and reworked the load with new brass and much less powder. Nosler developed data with the same bullet and powder yet even less powder, Im ok with that they have pressure testing ability I don't so I will use proven data from them. I have yet to blow a primer I hope I never do. The variables in dimensions, case capacity and lot to lot changes with powder make me very skeptical of things like Quik Load and any other calculated  un shot data. After re reading your total posts about this situation I think your def on the right track. Learning happens some times easy and harmless and others its HOLY BLEEP lets not do that again. Best wishes for good shooting.

    Indeed!

    The only oddity is I re read my load notes from 5 years ago when I first started using this bullet and no pressure signs were evident in any of the loads then and that was using CCI200 primers.  Rather that fight it, you listen to warnings like this, learn from them and move on.   The one major difference between then and now, is that then I used to neck size and now I FL size all the time.

  10. Sort of...I still have to work out how a charge of 0.8 under book max resulted in blown primers.  The only theory I have for that is that the bullet bearing length, hence friction, is greater on the flat base 60gr Vmax than predicted for the hpbt.  That, in itself and especially for the 1/8 twist might account for the pressure difference along with a slightly hotter batch.  

  11. Of the ones in the photos, quite honestly the heavyweight Mora (not the standard thickness, this one's a bit heavier and the better for it) gets the most use so I have a few of those, one kept in my stalking bag.  The green handled one is my custom skinner and general bushcraft knife but in spite of the fancy pants steel that had to be specially heat treated, it doesn't keep an edge for  that long.  It's about the perfect blade shape though as my primary gralloching knife.  The accolade for the sharpest blade and the one to hold an edge the longest goes to the razor sharp Helle Harding which makes for a really good lightweight general bushcraft knife but I use it mainly as one of my fishing knives and as a back up stalking knife for more delicate cutting tasks.  The top one uses fantastic crazy-sharp Chromo-Vanadium steel and keeps a wicked edge for ages, just needing the occasional strop but is too large as a hunting knife and is really an all rounder which I use on camping trips.

    Point is, I haven't yet come across the ideal one-knife-does-it-all design or steel so have a collection for different tasks. 

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  12. Major edit and an embarrassing admission.  It was not N130 (not even I would have loaded that far over book!) it was N133.  Max charge for a hpbt was listed as 24.7gr so I was well below this on my loads.  Redoing the Pmax calculator, it sows things in a more sane light, thankfully.  The primers blowing and the high MVs still point towards a fairly peppy powder batch just opened, so the lesson learned is re-do load dev for each now powder batch.  Batch to batch variations can be significant as I found out yesterday.

    New PMax calc , 27.5hr H20 ccase capacity, 23.9gr N133, 26 inch 1/8 barrel:

    56.4 Kpsi; 3159 fps.

    Actual avareged MV over 10 shots was 3236fps.

    Still a peppy load but nowhere near what I would have expected to blow primers.  I checked and the case heads are not bowed, and primer pockets are still nice and tight, so brass is A1 ok.  

    Still, clearly over pressure so backing off to closer to 23gr seems sensible.

     

     

  13. 34 minutes ago, KABOOM said:

    70776psi!! wow almost a proof load , That requires backing off the powder !Does the published data show this charge weight? Do you weigh each charge? Mixed cases can cause trouble, I would rework the whole load for safety.  

    Errrrr, yes, no, yes, no mixed cases involved and yes! 

    I've been reloading for years, shooting LR for years and slipped up on this one load more because of an adjustment to seating depth from the original load taking up effective powder volume and a batch to batch increase in powder energy.  Having a hot load to start with, shaving off around 20 thou on seating depth and using a slightly hotter powder resulted in primers blowing.  I'll be reworking the load for about a 42 to 42.5grn charge which is close to another accuracy node.  The irony is I've been suing this charge for the past 4 years and only had an issue once before when using 20 thou primer cups rather than heavier cups needed for 223 hot loads.

  14. Yes.  My actual velocities averaged 3224fps with a few higher than that 3244fps so 61fps under predicted but close.  Previous load data shows velocities at 3150fps with an SD of 5 and a low ES as well, so lower pressure (same cases).  Batch to batch variations in powder could easily account for the change.  Lesson learnt the hard way and one gas cut bolt face later.  Thankfully still useable!

  15. I tested my case volumes when I went from Lapua to Sako...they were within half a grain, give or take a little.  It's a slightly compressed load and they're seated to book COAL but could drop the pressure off by seating them out a little as my chamber's been reamed to accept 80grn heavies.  I've found that power manufacturer's COAL (which they use in testing) usually results in good loads, but I'll play safe and knock at leats a grain to a grain and a half off my current loads as I only require MVs for the distances I shoot to be around the 3,000fps mark in these or a little less in boat tail equivalent weights.

  16. 5 hours ago, borbal said:

    Well, that is gratifying - thanks very much for that

    Interesting that a load which had previously shown up as "green" (under 51,450 psi) is now "orange" at 61k psi. What load was that...?

    Thanks again for your comments

    Geoffrey

     

    It was a very hot one!  About 23.9gr N130 under a 60gr Vmax.  Shot this load for 5 years without any issues or any eviden pressure signs such as flattened primers or marks on the case heads and it's shot really well, but recently I've had two batches of Vhit where MVs seem to have jumped by over 100fps using this load so I'm backing way off and re-developing the load to another accuracy node a grain or more down the load ladder.

  17. Tried comparisons of actual loads fired today in 6.5 and .223 and the powder burn rate re-calibration seems to have worked as in each case actual velocities were within 30fps for two 223 loads and to 6.5 loads but oddly a lot further adrift with a lighter .223 bullet where PMax over-estimated velocities by over 100fps.   I'd call that a good result overall though so feel a lot happier about using this.  What was a "safe" load previously in 223 is not a "red" load at 61Kpsi which certainly correlated to my blown primers today!

  18. I thought I'd try some #1390's  these to compare them with their 55gr soft point boat tails I normally use for deer as well as a new and slightly hotter 6.5 load for my 140gr SSTs in 6.5CM.

    For load development I'd been loading the 223 rounds singly and found a good accuracy node at 23.6gr N130.  Out in the field today I put up a small gong at 216 yds and found that magazine loading these in my 527 doesn't work!  The big open HP design snags on the ramp and if forced chews a lump out so it looks like I have over 100 of these to single feed when hunting!  I'm unsure if they were a wise choice for munty but we'll find out.  They put up about a 1.2 inch group at 216 yds which I was pretty happy with at 0.57moa in field conditions.

    The Creedmoor fared even better with under a one inch 5 shot group at the same distance.  I'd zero'd a new load for those at 100 yds and taking care they produced a 0.25 inch ragged hole. Superb accuracy (43.6gr RS62).  

  19. Litz's Appied Ballistics for LR shooters has a very useful and comprehensive table of gyroscopic stability factors in the tables within the book.  It lists  advocates anything  1.4 and above is good.  Above 2 with some bullets you can run into problems with jackets coming apart in the barrel depending on bullet construction, so as pops says it'll depend on the bullet.

  20. I never ever use Hermes...utter crap service most of the time with them.  When I used to accept deliveries,  you had to toss a coin to guess what day or week the thing would arrive, then toss another one to see if it was still in one piece.  When a consignment a few years ago was a month late, I called their CEO's office to lodge a complaint at the top after being rubbed off at every other channel and the boss just spouted how much they valued my business etc etc and did nothing about the lost item.  It did eventually turn up, packaging damaged from memory.   Not with a bargepole would I trust them with anything again.

    I never buy off anyone who insists on using them.

    For business, I use UPS or DPD every time.  Never had anything missing, come later than promised or damaged (as long as packing was good).

    I never use Parcelforce48 now either.  They tend to offer similar levels of customer service as Hermes, charge ten time the amount and for good measure every now and then the item gets a good bashing.  hy anyone uses them when it's cheaper quite often to use DPD beats me.

  21. Thank you Geoffrey.  Yes, I understand and once the case capacities have been measured, your load estimates don't seem to be too far off and certainly within 100fps of wehat I am getting, but as you say, err on the low side for MV.  I have found your stated pressures a bit on the low side for some loads V's velocities.  The small primers , especially with the small flash hole variety brass can have a very different pressure rise characteristic I think than standard large rifle primers when used with large rifle loads (specifically the 6.5CM/.308 palma brass).  Load development though always trumps modelled predictions which I treat as a good way of perhaps comparing powders and establishing starting loads.

  22. Thanks for this very useful tool Blueboy

    One thing if I may?  It does not differentiate between small or large primer size which is pretty significant when looking at .308 and 6.5mm cases.

    I shoot 6.5CM and the load for SRP Brass is very different for LRP brass to generate the same pressures, this mostly due to the different ignition energy of the primers in relation to the powder column.

    For example, if I use 47.5 grns useable case capacity and enter my bullet weith of 139 grains, using RS62, it should be close to 98% fill with 44gr RS62 (small primer brass) and result in a 24 inch barrel of close to 2700fps.  Your model predicts 2658 which isn't too far off but that's my data using SRP brass for 2705fps (20 degrees).  You wouldn't want to go there pressure-wise with LRP brass and a large rifle primer!  From actual data, 42grns RS62 under the same bullet at the same OAL using LRP brass gives closer to 2750fps and 42.5 grns gives just over 2800fps.

    There appears to be something missing from the model in terms of assessing pressure/velocity as this must account for primer ignition energy and bullet seating depth.

    Having tried it with all my loads it does  seem to be adrift for my 6.5 and .308 loads (under-estimates velocities by quite a bit but in .308).  Pressures modelled seem to be high compared with velocities shown for Vhit powders, and velocites significantly lower for RS powders than I achieve using RS50,  but bang-on for my 0.223 loads for all powders I use!.  In all cases I load with the bullet seated to the base of the neck.

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