by Tom Gaylord
Writing as B.B. Pelletier
This is Part 2 of a guest blog from reader Dennis. He sent this to me a month ago, but I got so busy that I forgot about it until he reminded me last week.
This is about the air rifle he really enjoys. If you’d like to write a guest post for this blog, please email me. Now over to you, Dennis.
Revisiting the BSA GRT Lightning XL SE: Part 2
By Dennis
BSA GRT Lightning XL SE.
This report covers:
- Introduction
- Mea culpa
- Process modifications
- Groups at 20, 30 and 40 yards
- Trajectory
- Conclusion
Introduction
In Part 1 I reviewed the BSA GRT Lightning LX SE (.22 caliber), discussed several issues and showed results of several groups shot at 15 yards. I was encouraged to extend the range beyond 15 yards and report back the results. Thus this Part 2.
If you have not yet read Part 1, you can find it via the link above. Feel free to check it out now. I’ll wait here for you.
Mea culpa
I apologize for the long delay in getting to this Part 2. I made the mistake of dry-firing my rifle. Nearly broke my heart. I cleaned the barrel with a few dry patches. Nevertheless, my little Lightning threw a temper tantrum until she settled down after a couple hundred rounds. Now that she’s calmed down a bit, we’re back in business.
Also, when I mentioned distances, these are not measured but only paced. So they are not precise but are pretty close, — within a foot either way.
Process modifications
At the greater ranges, the interface between the rifle and the gun rest seemed to be more critical. Inconsistent recoil motion in the gun-rest system was amplified and produced greater variation in point of impact downrange. After some experimentation, I found that lining the gun rest with adhesive-backed felt allowed the gun to move more smoothly in the gun rest, when in recoil, and seemed to result in a much smoother overall shooting cycle. In any case, I convinced myself that it helped me shoot tighter groups.
Here’s a photo of the felt-lined gun rest:
The adhesive-backed felt is available at craft stores.
In response to comments in Part 1, I also changed the targets to permit scoring similar to that used in Olympic competitions. You will note the difference in the targets below. The targets consist of concentric circles with diameters from ¼ inch to 2-1/4 inches in ¼ inch intervals. The central circles out to one inch are shaded.
Groups at 20, 30 and 40 yards
After zeroing (more or less) at 20 yards, the following four-shot groups were shot out to about 40 yards. The ammunition is the 14.66 grain H&N Field Target Trophy.
20-yard groups.
30-yard groups.
40-yard groups.
Note that after the first two groups at 40 yards (at the top and on the right) are low. The last group (on the left) was shot using a one-dot holdover. I think these groups are pretty good for an old man with shaky hands and failing vision!
The following table summarizes the groups.
Range in yards…………20…………..30…………….40
Group size CTC
Avg. of 3 four-shot……..0.52”………0.70”………….0.82”
groups
percent of shots
within 1/2” of……………92……….….67………………75
POI*
Average score
per shot*…………………7.5………6.75…………..….6.0
*Based on the average of 12 shots at 20 and 30 yards. Four shots at 40 yards with one-dot holdover.
Trajectory
In shooting the groups shown above, the average point of impact at each range was lower than expected. Had the scope been a little better zeroed, or the holdover been better determined, all shots could have been within a 1 inch target. To get a better feel for the trajectory the following set of targets was shot from 10 to 40 yards. This will hopefully allow me to better calibrate my shots in the future.
40-yard groups.
Note: there was some moderate and variable wind the morning this set was shot. Nevertheless, the groups were pretty good out to about 35 yards.
Conclusion
The BSA GRT Lightning XL SE is pretty accurate out to at least 35 yards. An experienced marksman could no doubt extend the effective range (i.e. hit a one inch target) to at least 40 yards. Pretty good for a mid-priced air rifle, and she’s a beautiful gun.
Dennis,
Thanks for the excellent write up. You are indeed a fine marksman.
Are you sure about the pellet speed? Do you have a chronograph?
All the reviews that I have read say that it shoots about a 100 FPS less than your 10 for 10.
Maybe that explains why all your longer range shoots are low.
Lovely to look at.. how is the trigger? Cocking force?
Thanks again for giving B.B. a much needed busman’s holiday…
-Y
Hey Yogi,
Thanks for your compliments.
No, I’m not sure about pellet speed. I don’t have a chronograph. I have tried to infer pellet speed by trying to match the trajectory shown in the 10 to 40 yards group of targets. Unfortunately, there are so many variables that this proves difficult. Nevertheless, I was able to get a pretty good match to this trajectory using ChairGun Pro by entering a speed of 665 fps – much less than the chrony 10 for 10, but very close to the manufacturers specification of 670. Again, there are so many variables that I can’t know for sure. Here are the main parameters I entered into ChairGun Pro: pellet weight 14.66; ballistic coefficient 0.0190; speed 665; zero range 20; sight height 2.90.
The trigger could be better. The second stage pull is a little long and heavy for my taste. So I need to hold the aim point longer than I would like. Perhaps in the future I’ll try to upgrade this.
Cocking force is a bit tough, but it gets better over time. I am tall and not powerfully built but in pretty good physical condition for near 69 years. I can cock the gun by holding the pistol grip in one hand and the barrel in the other. But I couldn’t do this when I first got the gun; I used the two hands-on-barrel technique the first few times out. Otherwise, my arms would get a bit sore. In a short period of time, things changed, probably because the cocking got easier, my arms got stronger, and my technique got better. BTW, you can see the two-hands-on-barrel technique in Rick Eutsler’s video review of this gun if you wish to Google it.
Dennis
Dennis,
Fine write up with lots of good illustrations. Very nice. I think of your shooting rest often. It seems an ideal set up especially for those that may not find themselves as steady as once before. Springers are a tuff nut to crack. Yours is a fine looker and good shooter. I think you have struck a nice balance between a steady support and good accuracy. I am glad that you went out further too. A 1″ spread is a good point to start working on various refinements. The changes are more obvious.
Great job,… Chris
Thanks, Chris! Always a pleasure to read your comments!
I still may one day do some parametric studies on the rest. I do feel that it is a trade off between steadying my hold and possibly introducing its own variables. I believe, but haven’t proven, that it would be better to have a single point of support, if I could hold steady that way.
Dennis
Dennis,
As Gunfun1 has said, you can play with pistol grip pressure. Since you have 2 points of support (which I think will be steadier than any single point support) you could try something like a Walmart plastic bag over each point. Plastic on plastic (2 layers) should provide a bit of “sliding” effect to recoil. Just an idea.
As for Chairgun and no chrony,… you could shoot at every 5 yards, aim at the bull for all shots, 5 shot groups, use the spread center for data and the keep adjusting the fps in Chairgun until the trajectory matches. That should get you real close to what yours is actually doing if all of the other parameters of Chairgun are entered close to being accurate.
As for hold over, hold the cross hair on the center of the group and the count the mil dots to the center of the bull,…. that is your holdover for that distance. You probably have figured that out a long time ago though. Maybe someone could use that tip though.
Best of wishes on continued happy shooting,… Chris
Thanks Chris,
Your recommended approach for Chairgun Pro is what I used to arrive at the parameters in my response to Yogi. However I used 10 yard spacing and 4 shots per group. One of the greatest revelations for me was the effect of scope height parameter on the trajectory. Once I got that about right, the pellet speed was easier to determine, and I got a pretty good match at 665 fps.
Dennis
Dennis,
That is what I thought and how it sounded, but there still seemed to be some doubt. It sounds to me as if you have it nailed down. The felt is a good idea. That should have some nice slide as well. The 2 layers of plastic idea for sliding was an adaption of the artillery hold, allowing the gun to move. In fact, it is something that I need to try myself. The foam gasket I have atop the front rest does have a bit of grip to it which might be a factor.
Good morning Chris!
I tried the foam gasket, but found the gripping to be a problem. The felt allows for a pretty smooth, artillery-like movement. Here I’ll try to attach a screenshot of my ChairGun Pro trajectory graph. If it attaches, you’ll see that it is a pretty good match to the trajectory shot in the backyard.
Dennis
Dennis,
I see that you have the kill zone set at 1″ as I do. I use the inch scale where as you use the mil-dot scale (to the right on the chart). I did not see the red arch did not go all the way to the top. If you increase the (sight in) range, that arch will rise and the ends will extend. I believe that is what it is called without looking. It could be the zero range. That gets you more shots in 1″ at a greater yardage spread. Just bump the sight in data up and see what it does. I try to not break the dashed line at the bottom. If it does break, you will also see the pellet rise (out of) the 1″ kill zone and then fall back in.
Just something to try incase you were not aware of it.
Chris
Right, Chris.
The chart is based on where I had zeroed the scope for the review (~20 yards). After determining the velocity that matched the trajectory, I used the Toolbox / Zero Range Functions / Optimum Zero Range to find the best zeros. Turns out they are 35.9 and 16.6 yards – according to ChairGun Pro.
I used the mildot scale to get the holdover for the 10X magnification I’m using. An inch scale would be more generally applicable – but I can already read that from the left scale.
Dennis,
Sounds like you have it under control very well! 😉 Your efforts have proven that someone can figure out their fps even without a chrony and playing with Chairgun.
I have never seen a blog on doing what you did. Many talk about it, but (you did it). 🙂 Also, those “many” probably have a chrony too and no need to do that.
Maybe if you are up to another guest blog “go around”,.. that might be something to consider. I think that it would help a lot of people without a chrony. It is really nice to do the test/shooting you did and have it verified visually with Chairgun program.
Just an idea,…. Chris
Chris,
I thought I was retired!
Well, I do have all the data, and I suppose I could write up a pretty clear explanation. And, it would help the chrony-less, like me calibrate their guns. Perhaps I’ll do it.
Dennis
Dennis,
🙂 It was just an idea. And yes,… retired means that you can do whatever you want,.. whenever you want,… if you want,… if at all. 😉
Oops! Actually, I did shoot at 5 yard intervals when determining the trajectory – 10 yard intervals when shooting for groups! Go figure! I guess I can’t remember what I did a few days ago even when I write it down!
About being retired, as you have correctly discerned, I was joking! I suppose I should learn to use emojis! 😉
Of course I will be happy to try to create a post about this. I enjoy solving problems and am happy to share solutions. Writing the blog post will just be another problem to solve – so I’m good with it!
Dennis,
5 is even better. That makes any data gleaned even more solid. The tuff part of any report would be/might be, explaining/illustrating the in’s and out’s/operation of Chairgun. It is pretty easy to use as you know, but for those that do not use it,… it is also a great tool to teach the understanding of ballistics. With a few clicks and some new data input, you can actually see the change in pellet path, flight, trajectory and impact,.. all in an instant.
You may have to ponder all of that for a few,… but thank you for taking the idea under consideration.
Oh, interesting thought about the plastic bags. That might make for smoother recoil. The felt lining works pretty well, though.
Dennis
Dennis,
Nice job! I especially like your collection of groups from 10 to 40 yards. I know you used some holdover, but it demonstrates the rise and drop in POI of a typically-sighted-in air rifle pretty well. I don’t think I’ve seen that done on a single sheet of paper before!
Thanks HiveSeeker!
Actually there were no holdovers used in the 10 to 40 yards sequence of groups. The idea was to observe the trajectory while seeing the effect of range on group sizes. A four-shot group was taken aiming at the red bulls eye at each range.
The only place I used a holdover was on the lower left target in the set of three targets shot at 40 yards. I just wanted to see if I could get the shots on target.
Again, thanks for your comments!
Dennis
Got it. Bet you got tired carting your pellet trap to all those ranges! 😉
Ha ha! Good point, HiveSeeker! Well, one has to get exercise somehow! And yep, you’ve got the right picture!
Very well written, very well reviewed, very nice gun, I especially like the dual cheek piece. I’m curious about the dry fire incident. I understand that without a pellet in the bore the piston was allowed to slam unimpeded to the end of its stroke. Catastrophic failure not withstanding what are some of the other consequences of dry fire? And why do you feel it had a temporary effect on accuracy?
I was about to ask the same question myself about the dry firing. Also agree the article was very well written and illustrated.
Kevin in CT
Thanks, Kevin!
You can read my response to Coduece about the dry firing. Trust me, I am no expert. I’m just guessing my way through that event.
Dennis
Hey Coduece,
Thanks!
I don’t really know about dry firing. Perhaps others are more knowledgeable. I figure that even without damage, there might be a difference in the amount of oil/lubrication blown from the cylinder into the barrel. I do know that the gun seemed to be less consistent in shooting, i.e. shot larger groups, for a while. Perhaps that was just my imagination? but it felt that way.
Dennis
Dennis,
Well done, and congratulations.
The vertical string at the top gets one’s attention. I produce those sometimes if I am shooting my Walther Lever Action too quickly as the CO2 cools everything and the power drops. I once did it on purpose with a Hammerli 850 (VERY accurate at shorter distances) and 16 shots tore an almost perfect inch long tear in the paper.
Michael
Thanks, Michael!
Interesting thought about the temperature effect. I had no idea about why the vertical string of shots. Perhaps a solution is to take more time between shots in order to let the temperature stabilize?
Dennis
Dennis,
Definitely. Wait 20 -30 seconds between shots with a CO2 air gun, and it makes a big difference (as does shooting in hot weather).
Michael
Dennis, your passion for the rifle shows through; nice job, nice report; thank you. =D
Thanks, Dave!
I’m just trying to learn as I go along.
Dennis
Hello Dennis
Thank you so much for highlighting what I consider a hidden gem rarely sold here in North America. In Great Britain, the BSA Lightning has long been a best seller. Hunters enjoy the short length, low weight, and even though most airguns sold in GB are compatible with the under 12flb legal limit for air rifles, this little gem is still capable of 900+fps in full dress for those with permits, and the real lucky neighbours to the south of me who have zero limit on airguns (in most states). With the inclusion of a gas piston, it appears BSA is counting on making airguns well into the future.
Just one question, Dennis. You were disappointed with the long, rather heavy 2nd stage of the trigger. I believe this trigger to be quite adjustable. Have you attempted making small adjustments at a time until the 2nd stage is more to your liking?
Thanks once again for your well penned article on a fine little air rifle.
Ciao
Titus
Titus,
How is the homemade air gun project going? That was (beyond) fascinating, to me.
Chris
I think that was Duskwight now if I remember correctly.
Hello Titus,
Thanks for your thoughtful comments!
I did try to adjust the trigger, but I couldn’t find a solution doing so. I think I just made it worse. Never did feel lighter. Perhaps someone who knows what they are doing would have better results.
Dennis