BC Help: RAW with .25 Poly and .30 cal

[SMH77]

Hey guys, I'm a bit new when it comes to BC's, but have been searching and have learned enough to know that the barrel used, velocity, distances, and specific pellet all have a bearing on the BC. I looked at the HAM BC database earlier today and, while it's a great database, I see that the testing was performed with an FX Impact-so I’m assuming that is the ‘FX smooth-twist’ barrel that was used on the gun during the BC testing (it wasn’t listed)? If so, is there a way I can ‘convert’ these BC’s to the LW, LW-Polygon barrels I’m using on my gun (a RAW HM1000x, currently being converted by Martin at RAW from a 'standard .25 cal' to a .25 cal Polygon barrel, with an additional setup in .30 cal with whatever barrel Martin selects)? I’m guessing nobody has the exact data, but my particular interest lies the .25 cal JSB Exact 25.4 grn and Exact heavy (and MkII) 33.95 grain pellets (through a Polygon barrel @ 900 fps from a RAW HM1000x) and a .30 cal JSB Exacts (44.75 grain & 50.15 grain) from the same gun. I’m also curious if there is data from the H&N Barracuda (31.02 grain, in .25 cal) pellets.

I'm interested in ranges from 40-100 yards for the BC information.Does anyone know where I can obtain this data for these pellets from these barrels (and even from a RAW HM1000x would be an ‘bonus, bonus’).

 

[Centercut]

That's a very good question, and one that I couldn't find on the internet. So, I think the best thing to do is to do it yourself. If you look at Chairgun Pro, it has an app that allows you to calculate your own BC. I took 3 shots to get my muzzle velocity. Moved the Chrony to 25 yards exactly, and shot 3 shots. Moved to 50 yards, and took 3 shots. Moved to 75 yards, and took 3 shots. Took the average of each three shot group, and calculated the 3 separate BCs. This way you have the exact BC for your gun and pellet combo. You could take an average of the 3, or use whichever one is correct for that distance. Why didn't I do it at 100 yards? Well, I didn't want to shoot my Chrony! . Another good thing about having separate BCs is that in Strelok Pro it allows you to enter up to 5 BCs to use for your gun/pellet combo. You enter the FPS and BC for up to 5 items and it uses that as a composite BC. Seems to work. Good luck!
Mike
PS., this thread should be in the Pellets, Projectiles, and Ammo section.

 

[Hynzie]

have you got a chance to run this by martin ,if anyone would have it he would im interested too ,i have a HM1000X 30 cal,,so martin is setting you rifle to shoot dual calibers would like to no about that could u elaborate

 

[SMH77]

"Hynzie"have you got a chance to run this by martin ,if anyone would have it he would im interested too ,i have a HM1000X 30 cal,,so martin is setting you rifle to shoot dual calibers would like to no about that could u elaborate

Thanks for the suggestion. I just sent him an email to ask if he knows the BC's for the JSB's in the barrels calibers I'm having him set up with (good idea). I just hesitate to bother him too much as I don't want to be a pain in the rear, slow down others' work, and delay getting my own gun back.

Regarding my conversion: I had purchased a RAW HM1000X from Martin at RAW last summer and have been enjoying it immensely-the accuracy has been phenomenal (my best 5 shot group at 50 yards to date has been .125" ctc with JSB lights). I weighed adding a .30 caliber rifle to my collection and was emailing Martin about it earlier in the year. It was then, back in March, that he shared with me his experimenting with setting up the .25 cal to shoot JSB heavies at speeds even higher than what he's setting them at now-and getting exceptional results, particularly out at longer distances. I've been a fan of using very heavy pellets for any given caliber to get flat shooting results, out to long ranges, with good accuracy and energy retention (I actually wanted to do this with a .20 cal setup, but it seems that .20 caliber is dying now, unfortunately, due to lack of pellets being produced).

Anyway, when he shared that with me, my first goal was to get one of the .25 cal 'hot and heavy' setups, but finances were a limiting factor for me. I really, really hesistated to mess with an already phenomenal setup to do a conversion, but in the end-after reading many other accounts of people being thrilled with the .25 cal 'hot and heavy' setup, I've decided I trust Martin enough to do an excellent job (not that I doubted he would-just didn't want to mess with something so superb). Thus I got quotes on converting my rifle. I also asked him how much extra it would be to have him set the gun up for .30 cal at the same time and send me the .30 cal setup so I could swap between the .25 cal 'H&H' setup and the .30 cal setup at will. Given that the regulator, hammer spring, etc settings are virtually the same, Martin said switching between these two setups would be a breeze (swap barrel / probe and you're all done). 

I finally decided to send Martin my gun last week to do the conversion. He received it on Thursday (same day I was to have hernia repair surgery) and said it would likely be 3-4 weeks to turnn the gun around. I figured that, since I was going to have to endure surgery-and have a mending period afterwards-I wanted something to look forward to on 'the other side'. Now I'm home, mending, and eagerly awaiting the return of my gun.

Let me know if you have any questions and I'll share what I can from what Martin has told me...

Sean

 

[SMH77]

"Centercut"That's a very good question, and one that I couldn't find on the internet. So, I think the best thing to do is to do it yourself. If you look at Chairgun Pro, it has an app that allows you to calculate your own BC. I took 3 shots to get my muzzle velocity. Moved the Chrony to 25 yards exactly, and shot 3 shots. Moved to 50 yards, and took 3 shots. Moved to 75 yards, and took 3 shots. Took the average of each three shot group, and calculated the 3 separate BCs. This way you have the exact BC for your gun and pellet combo. You could take an average of the 3, or use whichever one is correct for that distance. Why didn't I do it at 100 yards? Well, I didn't want to shoot my Chrony! . Another good thing about having separate BCs is that in Strelok Pro it allows you to enter up to 5 BCs to use for your gun/pellet combo. You enter the FPS and BC for up to 5 items and it uses that as a composite BC. Seems to work. Good luck!
Mike
PS., this thread should be in the Pellets, Projectiles, and Ammo section.

Thanks for the suggesting. I do have a Shooting Chrony (but only one), and I use Chairgun Pro too. I haven't seen the BC calculator tool in the app-I'll take a look for it. I think the best way to perform the test is use two chrony's, to measure the exact same shot, yes? Or, better yet, use one of the Labradar setups? I was going to look into buying a second chrony, but may try to sell my chrony and pick up a Labradar setup instead (price is high, but not astronomical-so its within reach).

I have heard others speak of Strelok Pro, but haven't looked into it. I will have to look it up to see what it is, does, etc to see if that is something I should look into also.

Yeah, I didn't know if this was appropriate for the PCP section (since it's specfic to RAW) or the ammo section. Sorry...

Thanks for the information!

Sean

 

[Imold]

Now I’m interested in the 25 H&H set up and cost...by the 30 instead of 25 and then do the conversion hmmmm you guys really know how to confuse a person..

 

[shutik]

I just wanted to add that chairgun pro has option to calculate bc based on point of impact drop at known distance.

This way you can measure speed at the muzzle. You'll need to know your far zero. Let's say 40 yards. Then you shoot at the Target further away, let's say 75 yards. Then you measure how many inches lower POI was at 75 yards and enter it into chairgun pro calculator as negative number, i.e. -5.

Once all input numbers entered, you hit calculate button.

 

[SMH77]

"shutik"I just wanted to add that chairgun pro has option to calculate bc based on point of impact drop at known distance.

This way you can measure speed at the muzzle. You'll need to know your far zero. Let's say 40 yards. Then you shoot at the Target further away, let's say 75 yards. Then you measure how many inches lower POI was at 75 yards and enter it into chairgun pro calculator as negative number, i.e. -5.

Once all input numbers entered, you hit calculate button.

Nice! I didn't know that. Is that in the iPhone app, or in the desktop version of the program? I'll have to play with that-once my gun comes back of course.

 

[SMH77]

"Imold"Now I’m interested in the 25 H&H set up and cost...by the 30 instead of 25 and then do the conversion hmmmm you guys really know how to confuse a person..

You'll need to get the quote from Martin, as it depends on what setup you start with (due to regulator settings, etc) to begin with. It should only be the cost of the barrel/shroud and the different size probe if you order a 'two caliber' option from the start (and the two caliber/powers are similar like I'm doing). Having said that, I may be overlooking something so I definitely don't want to speak on Martin's behalf-nor do I want to upset him by suggesting numbers here publicly. For me, starting with the 'lower power' (50 fpe) .25 cal setup, he did say there was a good bit of internal modification that needed to happen to my gun to get it setup for the H&H setup-more so than just adjusting the regulator and hammer spring tension. In fact, some of the 'extra parts' he quoted me included a new, heavier, hammer spring as one of the parts needed.

I'm really looking forward to the new setup-this really will give me the two caliber combo I really want.

 

[Imold]

When my HMx .357 is done and in my hands I’ll talk to Martin again and ask him about the .25-.30 conversion in a HMx LRT....kill two birds with one stone sort of.

 

[SMH77]

"Imold"When my HMx .357 is done and in my hands I’ll talk to Martin again and ask him about the .25-.30 conversion in a HMx LRT....kill two birds with one stone sort of.

I actually did talk to him about doing something based on the HMx action, and he said it was a 'no go' because the actions were too different. I was hoping for a 'high power' version of the .30 cal that I could convert into a .357 cal as well (or something like that). I'll be curious to see if you find an option for the HMx action-would be interested to know what would be available with that one for an 'even higher power' setup.

Err, perhaps (going by memory) the issue was that the HMx (or super high power .30 cal) wouldn't be regulated (one of the things I was trying to maintain with my setups)? Perhaps I'm wrong-it's certainly worth an ask to see what he suggests...


Sean

 

[shutik]

"SMH77"

"shutik"I just wanted to add that chairgun pro has option to calculate bc based on point of impact drop at known distance.

This way you can measure speed at the muzzle. You'll need to know your far zero. Let's say 40 yards. Then you shoot at the Target further away, let's say 75 yards. Then you measure how many inches lower POI was at 75 yards and enter it into chairgun pro calculator as negative number, i.e. -5.

Once all input numbers entered, you hit calculate button.

Nice! I didn't know that. Is that in the iPhone app, or in the desktop version of the program? I'll have to play with that-once my gun comes back of course.

Only desktop version of the program. I can upload screen shot where it is in the menu once I get home.

 

[Imold]

The .357 action is in its own league it’s built bigger then anything else in the RAWs line up...

 

[SMH77]

"Imold"The .357 action is in its own league it’s built bigger then anything else in the RAWs line up...

Yeah, I just revisted the RAW website and see where he reiterates the HMx action won't interchange with any other caliber. I'll have to keep an ear out for how you like yours for coyote hunting (was just reading another post in the hunting section where you mentioned the HMx would be for dogs). I haven't shot any dogs or fox, but we have plenty around me (and they are BIG too-like bigger than German Shepard size, BIG). I'm not sure if the .25 high power will handle one, but I suppose a well placed head shot will do it in just fine! If I prefer more power to play it safe, then I'll put on the .30 caliber barrel instead...

 

[Imold]

Folks due take yotes with the 25 caliber but it’s done with head shots and that can be a bit unethical as far as I’m concerned at far distances, to big of chance of just wounding a animal that’s why I have chosen the HMx .357 regulated to 130ft/lbs, I do have the .357 BullDog and the Texan in .45 but I like what the HMx has to offer and think it will be perfect for yotes under 100 yards, I just dont see using my wildcat for yotes, squirrels and rabbits absolutely, if I want to take yotes at farther distances I have my 22-250 which is sighted in at 200 yards just for yotes.
My main thing with getting a HMx .25 LRT is for strictly bench shooting and if I could get a 30 conversion for it that would just double my opportunity on the bench. I do have a Hatsan BT65SB Elite QE that I’m shooting off the bench now and does fine but getting a designated bench .25 would be nicer in my book. This airgun stuff never ends its worse then Powder Burners........

 

[shutik]

Attaching screen shot of ChairGunPro menus, as promised. 

 

[SMH77]

"shutik"

Attaching screen shot of ChairGunPro menus, as promised.

Awesome-thank you very much for that! Will look into that once I get my gun back from Martin.


Sean

 

[SMH77]

"SMH77"

"Hynzie"have you got a chance to run this by martin ,if anyone would have it he would im interested too ,i have a HM1000X 30 cal,,so martin is setting you rifle to shoot dual calibers would like to no about that could u elaborate

Thanks for the suggestion. I just sent him an email to ask if he knows the BC's for the JSB's in the barrels calibers I'm having him set up with (good idea). I just hesitate to bother him too much as I don't want to be a pain in the rear, slow down others' work, and delay getting my own gun back.

Regarding my conversion: I had purchased a RAW HM1000X from Martin at RAW last summer and have been enjoying it immensely-the accuracy has been phenomenal (my best 5 shot group at 50 yards to date has been .125" ctc with JSB lights). I weighed adding a .30 caliber rifle to my collection and was emailing Martin about it earlier in the year. It was then, back in March, that he shared with me his experimenting with setting up the .25 cal to shoot JSB heavies at speeds even higher than what he's setting them at now-and getting exceptional results, particularly out at longer distances. I've been a fan of using very heavy pellets for any given caliber to get flat shooting results, out to long ranges, with good accuracy and energy retention (I actually wanted to do this with a .20 cal setup, but it seems that .20 caliber is dying now, unfortunately, due to lack of pellets being produced).

Anyway, when he shared that with me, my first goal was to get one of the .25 cal 'hot and heavy' setups, but finances were a limiting factor for me. I really, really hesistated to mess with an already phenomenal setup to do a conversion, but in the end-after reading many other accounts of people being thrilled with the .25 cal 'hot and heavy' setup, I've decided I trust Martin enough to do an excellent job (not that I doubted he would-just didn't want to mess with something so superb). Thus I got quotes on converting my rifle. I also asked him how much extra it would be to have him set the gun up for .30 cal at the same time and send me the .30 cal setup so I could swap between the .25 cal 'H&H' setup and the .30 cal setup at will. Given that the regulator, hammer spring, etc settings are virtually the same, Martin said switching between these two setups would be a breeze (swap barrel / probe and you're all done). 

I finally decided to send Martin my gun last week to do the conversion. He received it on Thursday (same day I was to have hernia repair surgery) and said it would likely be 3-4 weeks to turnn the gun around. I figured that, since I was going to have to endure surgery-and have a mending period afterwards-I wanted something to look forward to on 'the other side'. Now I'm home, mending, and eagerly awaiting the return of my gun.

Let me know if you have any questions and I'll share what I can from what Martin has told me...

Sean

I heard back from Martin this morning and he said 'he did not know what the BC was for the pellets I inquired about'.

 

[Imold]

So how much for the conversion from the HMx .25 H&H to the 30 cal ?? 
That right there will have me ordering another RAW HMx .25 if it’s doable and priced right.

 

[SMH77]

"Imold"So how much for the conversion from the HMx .25 H&H to the 30 cal ?? 
That right there will have me ordering another RAW HMx .25 if it’s doable and priced right.

I'm not sure whether or not Martin can build a HMx based action with .25 cal or not. I guess I didn't ask that question. He said the HMx action was for .357 cal. I would recommend contacting him to see what options are available for the HMx action. To my, and this is just my opinion, it sounds like the HMx action could be the basis for larger caliber rifles-the .357 perhaps being the smallest option. I wonder if he's experimenting with anything above .400 for larger bore options for future models? Who knows...

If a high power .25 cal is what you're after, right now that sound like the H&H version I am ordering (based on a HM1000x action). Let me know if Martin shares any insight on HMx calibers for down the road.