Overview

I read that the sus nozzle of the GDR-15 hurts the BB bullet when firing and loading, which adversely affects the shot grouping, so I decided to experiment.

Experimental Environment

indoor, no wind
10M
GDR 15 2023 production ver.
0.2 rounds (from BLS)
5 rounds per target
Same position, shooting while seated

Control and experimental groups

First column (slow): without batteries, loading with slow cylinder advancement to avoid wounding the BB.

Second column (bolt catch): Without batteries, loaded by pressing the bolt stop after locking the bolt retraction.

Third column (battery): Used battery to fire.

Expected results before the experiment

Expected that the first line (slow) would produce the best rounds.

Experimental results and interpretation

third row (battery) was the best, then the first row (slow), and lastly the second row (bolt catch)
Difficult to notice the difference between the bullets except for the second row (bolt catch), which performed exceptionally well.
Possible that the better-quality rounds were clustered in the second row.
A repeat test with a better-finished bullet (Marui) would be required for accurate results.

Conclusion

While this may be a limitation of the BLS 0.2 bullet, it is unlikely that the sus nozzle is damaging the bullet.

It is likely that the Marui bullet will improve the cluster performance even more.

Extras

I got lucky and got 5 BLS shots in a row that were well placed.

Not bad huh

I don't think I've ever like this before.

Left: Marui MWS, Right: DAS GDR-15

MWS: changed the inner barrel, hop-up rubber, and bolt catch roller installation + Marui 0.2 bullets.

Summary

I read that the GDR15's sus nozzle hurts BB bullets when firing and loading, which adversely affects shot grouping, so I experimented.
I need to experiment with better bullets to get accurate results.
DAS is crazy accurate