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View Full Version : Couple things i would like to talk about.



skeetlee
05-23-2010, 01:22 PM
I went to the range this morning to work a load for the up and coming East west shoot in St Louis. I got my hands on a couple different BT bullets for the ppc and they shot really well today. What i noticed though was my charge weights with 08 n133 were down from were i normally shoot the FB bullets. With a FB bullet i run around 28.8-29.2gr. with these Bib and Hottenstein bullets i was down to 28.4. Like i said they shot great so no complaints there. What i kinda wonder is since the temps today were in the 80's and humid, is that the reason for the reduced charges? Basically what i would like to know is if the hotter more humid it is, do you general reduce charge weights? That seems to be the case today for me, although the last time i shot this barrel i shot FB bullets and not BT bullets. Or is the reduced charge weight a direct result of a BT vs a FB bullet. Do you general shoot BT bullets with a lower powder charge? I hope all that makes since. LOL!!! I just love this stuff, and i like learning as much as i can about it.

The second thing i would like to discuss is my new Leupold 45x. I set this scope in a set of Bat 20moa 30mm rings. Of course i had to dial the difference of the 20moa to get on paper. What i noticed was that because i had to dial so much to compensate for the 20 moa the image wasnt as clear as it was when the scope is dialed directly in the middle of the MOA range. Is there a tube or something inside there that distorted when i dial that much. I was almost to the very end of the dials to get on paper @ 100 yards with these rings. Is that normal. The scope is really clear when it sits in a standard Kelby/Davidson 0 moa set up. but with these 20moa rings it just wasnt as clear!!

Finally i would like to talk about the eye relief on the 45X. I kept getting whacked with the dam scope today. I know that sounds funny, but i am not sure what i can do about it. I like to shoot free recoil and i didnt think my shoulder was all that far behind the butt. No matter what i tried i got hit. This kinda stinks!! Has anyone else experienced this with a Leupold 45X. I reckon the eye relief is just shorter than a 36X??
These are just a coupe of my experiences today fellas and i would like to learn a little something, plus I dont have anything else to do this afternoon!! LOL!! Have a great Sunday men!! Lee

old 4 and 1
05-23-2010, 02:17 PM
I just started shooting free recoil and i also have gotten bit a couple of times. I find i am leaning into the scope so that i can get a wider field of view. I am going to try moving the scope back an inch or so and keep my body more upright and see if that helps.

Gary

Boyd Allen
05-23-2010, 02:26 PM
I will leave the effects of heat and humidity to others except to say that if one has the room there may be an option of going up quite a bit as an alternate to going slightly down...if you have enough room in that direction pressure wise, the problem being if you go a little ways up and it doesn't work you may quit too soon.

As to the image quailty thing...Lens systems give their best performance when they are collimated. http://en.wikipedia.org/wiki/Collimated_light (scroll down) The way that an internal adjustment scope works, an internal tube, the erector tube, that pivots at one end, is adjusted so that the superimposed position of the reticle on the target will give the desired point of impact. At the extreme that you have described, the erector is looking through the edge of the objective, rather than its center, reducing image quality, because the centers of all of the optical elements are not aligned.

Have you tried moving your scope forward? I tend to set mine up so that I have to lean into it a bit to see the full field of view. I have also learned that if I can see a little black around the edge (shooting at the bench) I am less likely to suffer a scope to nose collision.

LHSmith
05-23-2010, 02:29 PM
V133 requires a humidity gauge. Do a search.....there's got to be 20 pages on this topic.

skeetlee
05-23-2010, 03:19 PM
I am more interested in learning if there is a general opinion that a BT Bullet takes less powder compared to a FB? I will do a search and see what i can find on the humidity effects. I have read about it before but it seems a bit overwhelming for this country boy. I will learn it though!!
So Boyd are you saying that there might be another load range a bit higher up the charge scale? Is there much to gain by going faster and more pressure? The rifle is shooting in the 1's at 28.4. Thanks a bunch! Lee

Boyd Allen
05-23-2010, 03:51 PM
Given how it is shooting, i am NOT suggesting that you change anything. What I am referring to is that 133 is reported to have multiple accuracy nodes, and that Gene Beggs has reported that with the typical Benchrest barrel lengths and weights, that they are approximately 1.2 grains apart. If you are slightly above a node and you go up say .3 things will probably get worse, which may lead to the incorrect conclusion that there is nothing to be gained by going up, while a similar step down will put you on a node. I have found his information useful.

LHSmith
05-23-2010, 04:08 PM
Also consider that age old question, how do you know that charge you measured previously is the same density( i.e. identical latent heat content) as the charges measured today? A good diagnostic may have been to also try some FB's to compare.

skeetlee
05-23-2010, 04:50 PM
If you are slightly above a node and you go up say .3 things will probably get worse, which may lead to the incorrect conclusion that there is nothing to be gained by going up, while a similar step down will put you on a node. I have found his information useful

This is a great statement as this is exactly how i found this tune today. I have been having an issue with a sticky bolt after firing so i didnt want to go up any much past 28.8, so i went down in powder. 28.6 shot a solid .250 but the 28.4 was a dot. I repeated the load and another dot! I will continue to shoot this load next time at the range. I bought this barrel with 106 rounds on it and this is the second time i have shot it.the first time out i had only 4 loaded rounds and the charge was 28.8gr with a George Ulrich BT. The barrel also produced a very small 4 shot dot. the temperature was around 55. The ogive is also much different on the Ulrich as apposed to these BIB 68.5gr BT i have now. I did order some Ulrich bullets and i will have them before long. I do wish i would have packed some FB bullets as well today but i didnt think much about it, because this barrel is showing so much promise with the few BT i have shot through it.
I guess this goes to show me just how sensitive the ppc can be to current conditions on a given day. Now the question is to know when and how do you find this proper tune during the match? Maybe this is why i am so drawn to the hole ppc thing. It keeps me working and i enjoy that. Thanks Fellas! Lee