jfh
Member.
Some various responses here--
Marvin Knox: I think I would sight in your M&P 340 this way:
Now I would proceed to shooting the practice ammo and determining what change there may be from the factory ammo POA, at the same distance. If you find the difference to be distracting, readjust the laser as needed to shoot to the POA for the practice ammo you have, and at the practice distance. Note the adjustment needs--i.e., how much of a turn you apply for both windage and elevation, and readjust for each ammo.
Overall, however, I am with DAdams--the laser dot shakes so much that, without a Ransom / whatever brand rest, the repeatability is difficult. Off a bench rest, I can get sub-1" groups, 8 or 9/10 with CFs, at 10 to 15 yards--but that's currently the limit of my eyesight. If you can do better, caveats. IMO the inherent accuracy is there. (See Stephen Camp's j-frame ammo reports from j-frames.)
Keep in mind that "sighting in" a defensive handgun is meant to maximize the defensive capability of the user, and not the inherent accuracy of the firearm. Generally, I consider the two goals to be conjunctive--but I do not "think about" inherent accuracy when I practice, I emphasize practical accuracy.
DAdams: If the road is not a mess, I may actually get to the range this week to begin testing the various loads I've worked up this winter. After last week's snow storm, the temp hit 69F yesterday.
Most of the new development has emphasized reloads for the "FBI-load" ballistics. At the most basic level, that's a 158-gr. LSWC-HP running at about 800-820 fps from a 2" barrel. (Again, see Stephen Camp). It's a 38+P load, per the Remington 38S12 and the Georgia Arms 38E product numbers.
I have got that replicated now--e.g., the "replica recoil" testing--with both Speer 158LSWC-HP and various brand 158-gr. LSWC bullets and with various powders. Historically, the preferred "retail" powder for doing this has been SR-4756--and I am beginning to see why, I think, but I'll know shortly if the chrono tests hold up.
There is also a "38+P+" load with enhanced ballistics--originally loaded in 38 Special cases, but with LOA set to 357 Magnum. I've moved this load into 357 cases--why hotrod 38 Specials if the revolver shoots 357 Magnums--and this load is stout in a 340, but entirely (re-) shootable. This one should run about 875-900 fps, I think, and it really is a "357-light" load: I estimate the pressure to be about 24,000. I'm projecting the velocity for this round to be approaching 900.
Caution: this is an over-spec load for current 38+P SAMMI standards, and should be shot only in modern handguns.
(The THR disclaimer).
As for those 158-gr. Buffalo Bore loads--no, the only ones I've shot so far have been their 38+P+ / 158-gr LSWC-HP that runs 1000 fps from a 2" barrel. (That's reported on earlier in this thread.) I carried this load through the winter, but I will probably go back to the GDSB 38+P 135-gr. load and emphasize better / faster quad fives.
Jim H.
Marvin Knox: I think I would sight in your M&P 340 this way:
1. Determine at what distance you shoot to POA with your selected factory PD ammo. For the sake of discussion, let's say that is the GDSB 38+P 135-gr. round. Use the hold / sight picture you are most comfortable with.
Further, do this off a benchrest, but use your two-handed grip (see the Jerry Miculek videos for j-frame grips) and rest your grip on sandbags, not the 340. This procedure minimizes POA issues with grip shift, which readily occurs with the smaller / shorter grips.
2. Further, I'll assume that this 38+P round shoots to POA at 15 yards.
3. Now set the laser to shoot to POA at 15 yards--i.e., when you shoot, the (laser) dot disappears.
Further, do this off a benchrest, but use your two-handed grip (see the Jerry Miculek videos for j-frame grips) and rest your grip on sandbags, not the 340. This procedure minimizes POA issues with grip shift, which readily occurs with the smaller / shorter grips.
2. Further, I'll assume that this 38+P round shoots to POA at 15 yards.
3. Now set the laser to shoot to POA at 15 yards--i.e., when you shoot, the (laser) dot disappears.
Now I would proceed to shooting the practice ammo and determining what change there may be from the factory ammo POA, at the same distance. If you find the difference to be distracting, readjust the laser as needed to shoot to the POA for the practice ammo you have, and at the practice distance. Note the adjustment needs--i.e., how much of a turn you apply for both windage and elevation, and readjust for each ammo.
Overall, however, I am with DAdams--the laser dot shakes so much that, without a Ransom / whatever brand rest, the repeatability is difficult. Off a bench rest, I can get sub-1" groups, 8 or 9/10 with CFs, at 10 to 15 yards--but that's currently the limit of my eyesight. If you can do better, caveats. IMO the inherent accuracy is there. (See Stephen Camp's j-frame ammo reports from j-frames.)
Keep in mind that "sighting in" a defensive handgun is meant to maximize the defensive capability of the user, and not the inherent accuracy of the firearm. Generally, I consider the two goals to be conjunctive--but I do not "think about" inherent accuracy when I practice, I emphasize practical accuracy.
DAdams: If the road is not a mess, I may actually get to the range this week to begin testing the various loads I've worked up this winter. After last week's snow storm, the temp hit 69F yesterday.
Most of the new development has emphasized reloads for the "FBI-load" ballistics. At the most basic level, that's a 158-gr. LSWC-HP running at about 800-820 fps from a 2" barrel. (Again, see Stephen Camp). It's a 38+P load, per the Remington 38S12 and the Georgia Arms 38E product numbers.
I have got that replicated now--e.g., the "replica recoil" testing--with both Speer 158LSWC-HP and various brand 158-gr. LSWC bullets and with various powders. Historically, the preferred "retail" powder for doing this has been SR-4756--and I am beginning to see why, I think, but I'll know shortly if the chrono tests hold up.
There is also a "38+P+" load with enhanced ballistics--originally loaded in 38 Special cases, but with LOA set to 357 Magnum. I've moved this load into 357 cases--why hotrod 38 Specials if the revolver shoots 357 Magnums--and this load is stout in a 340, but entirely (re-) shootable. This one should run about 875-900 fps, I think, and it really is a "357-light" load: I estimate the pressure to be about 24,000. I'm projecting the velocity for this round to be approaching 900.
Caution: this is an over-spec load for current 38+P SAMMI standards, and should be shot only in modern handguns.
(The THR disclaimer).
For now, here's an existing recipe to use for the 'standard' 38+P FBI load:
about 6.2 gr. of SR-4756 under a Speer 158LSWC-HP, firmly crimped at mid-cannelure. LOA will be about 1.460, depending on your cases.
The 357-light load uses about 6.8 gr., with a similar crimp and LOA at about 1.590+.
about 6.2 gr. of SR-4756 under a Speer 158LSWC-HP, firmly crimped at mid-cannelure. LOA will be about 1.460, depending on your cases.
The 357-light load uses about 6.8 gr., with a similar crimp and LOA at about 1.590+.
As for those 158-gr. Buffalo Bore loads--no, the only ones I've shot so far have been their 38+P+ / 158-gr LSWC-HP that runs 1000 fps from a 2" barrel. (That's reported on earlier in this thread.) I carried this load through the winter, but I will probably go back to the GDSB 38+P 135-gr. load and emphasize better / faster quad fives.
Jim H.